AS Liberal frontbencher Sophie Mirabella stood at the funeral of her old friend Colin Howard, QC, at Melbourne Cemetery on September 11, she gave a brief speech about his legal career.

A general counsel to the federal attorney-general, dean of law at Melbourne University, monarchist, author of legal textbooks, it was a long and distinguished professional life.

What Mirabella did not mention, what she had never admitted even to her family, was that Colin Howard, 40 years her senior, was also her live-in lover for five years in the late 1990s. She did not mention that she had received gifts from him worth well over $100,000 to help her preselection, and then election in the federal seat of Indi in 2001, and another substantial sum to buy her Wangaratta farmhouse in 2007.

Nor did she say that she was the executor of his will and, his family believes, its sole beneficiary. If this is the case, she stands to inherit Howard's $ 1million house in a prime street in Carlton.

Neither did she say that Howard had lived for nearly a year in a cottage they rented for him near Mirabella and her husband, Greg's, country farmhouse as his mental and physical heath deteriorated, he grew incontinent and paranoid, and eventually had a fall that nearly killed him.

These facts are now part of an acrimonious dispute with Howard's daughter, Lesley, and son, Mervyn. Hostilities were suspended earlier this month as they all stood metres apart around a ginkgo tree at the cemetery to remember him and inter his ashes. But if Lesley and Mervyn do not receive answers to their questions, they will mount a Supreme Court challenge in coming weeks.

Mirabella declined to answer questions yesterday, saying only: "It is less than 12 days since Dr Howard was buried and no application has been made to obtain grant of probate of his will. There is no public interest in denigrating the memory of a private man."

This story begins in 1994, when young solicitor Sophie Panopoulos first met the man she described in her maiden speech in the House of Representatives as a man whose "intellectual ability and integrity" had inspired her.

By the following year, they were romantically linked and living together - she, born in 1967, at the start of a legal career and he, 40 years her senior, nearing the end of his.

Despite raised eyebrows, young Sophie Panopoulos was accepted into the families of Mervyn and Lesley Howard. In 1995 she travelled with Colin to visit Mervyn, a UK-based fund manager who helps administer the business interests of the Sixth Duke of Westminster.

But Panopoulos's family and friends were not allowed to know about her relationship. For six years, she and Howard visited Lesley and her family on Christmas morning before Howard returned to their shared house in Carlton, and Panopoulos went to see her parents, who were blissfully ignorant of her living arrangements.

In 1997, Lesley Howard says Panopoulos even involved her in the subterfuge of co-signing a lease on a flat in South Yarra where she could leave some clothes and pretend to live if she had to invite around family or friends.

As it turned out it was not required: "The only time she came to the flat apart from setting up the deception was to conduct a joint garage sale with me," Lesley Howard, a statistician now working for a charity, told The Age.

In 2000, Panopoulos moved to Wangaratta to seek Liberal preselection for the northern Victorian rural seat of Indi. Howard was an enthusiastic campaigner on her behalf. He lent her his car, a Pajero, to campaign in, and he paid campaign expenses to the tune of $100,000 to help her win the seat.

He did so because he was proud of the woman he described in November 2000 as starting out a ''brave but stranded young political fringe dweller'' who, with ''a touch of political genius'', had become a ''Liberal legend''. But she had also promised him that she'd employ him in her electorate office should she win the vote.

''As she said to me the other day, if she wins this election, she is made for life,'' Colin wrote to Mervyn at the time.

But soon after the election win in 2001 they began to grow apart. At 74, Howard was finding the drive between Melbourne and Wangaratta difficult. The job in Panopoulos's office never eventuated because, she told him, her backbencher's staff entitlement was not sufficient to employ him.

Sophie Panopoulos moved on. In 2002, she met and formed a relationship with another man.

Colin Howard went back to his life. Always socially awkward, his circle shrunk to include only his two children and the owners of his local restaurant Abla's, where he ate alone almost daily, and where they still refer to the table where he sat for so many years as "Colin's table".

Howard and Panopoulos also kept in touch. He continued to feel strongly towards her, and she visited him and helped out in 2003 when he had surgery on his hand. When Mervyn visited Colin in 2004, he saw evidence of her "nail polish and cotton pads" in Colin's Carlton house.

But it was clear to Mervyn on that visit that his father was finding life more and more difficult. He was normally fastidious about his surroundings, but the house was filthy, the floor covered in straw, suffering subsidence, and in need of significant maintenance. Mervyn and Lesley paid for the house to be cleaned, and for a regular cleaner.

But through 2005 and 2006 it seemed to Colin Howard's children that his condition was deteriorating. Mervyn and Lesley now believe that he was showing early signs of the Alzheimer's disease that he would finally be diagnosed with in 2008.

Lesley said he started showing up hours before dinner was due to start because of his fear of getting lost along the previously familiar route.

Letters show his handwriting becoming progressively childlike. He lost the ability to use his TV and stereo, and one day became hopelessly disoriented on the way to his doctor in the city.

In 2006 he complained in a letter to Mervyn about having ''developed … a habit of sleeping so restlessly that I kept falling out of bed. No real harm has been done but I'm short of sleep and not too keen on beds.''

A heartbreaking letter that year suggested a growing paranoia about the payment of his cleaner, who was also doing his shopping and other housework.

The cleaner, Heather Colston, said his deterioration in 2006 was ''very sad''.

''His mind was definitely troubled. He was very suspicious … There was a park outside his home with lots of young mothers with babies. He was suspicious of them, that they were spying on him, looking at him.''

He was unwavering in his high regard for Sophie Panopoulos, but sometimes believed that Mervyn and Lesley were involved in a conspiracy against him.

In June Sophie Panopoulos married Lieutenant-Colonel Greg Mirabella. Howard attended the Wangaratta wedding. Cleaner Colston said he'd told her: ''I went to the church very early. I was there about three or four hours ahead of the service.''

But during Mervyn's family visit at Christmas 2006, he and Lesley became even more worried about their father and whether Sophie Mirabella was influencing him. Colin told Mervyn he had given his former partner a sum of money large enough that he had to cash in one of his pensions. The money, he said, was to help her buy a house, because she and Greg could not afford it alone. Mervyn suspects, but does not know, that it was in the order of $100,000. Of further concern to Mervyn was his father's comment that Sophie Mirabella had asked him not to tell anyone about it.

Property records show that in March, just weeks after this conversation, Sophie Mirabella bought a house in Wangaratta for $695,000. That purchase is recorded in her parliamentary register of members' interests, but no gift is recorded. (Gifts from personal friends are not required to be recorded if there is no appearance of a conflict of interest.)

After Mervyn had returned to England, he quizzed Mirabella about money. In a measured email send on January 6, 2007, he asked, ''Do you and your husband think it is appropriate to be accepting a gift like this from Colin?

''You should not think this is a jealous snipe from a financially self interested family member - I have no need for Colin's money,'' he wrote.

''I question whether you have the right perspective on this when your family now has two incomes and he has no new sources of capital and will require increasing assistance as time goes by.''

Mirabella's response the following month was furious. ''The words you have chosen to use are both incorrect and insulting. I do not expect that you ever did or ever will understand Colin's relationship with me,'' she wrote.

''Whatever Colin may have gifted to me was neither solicited nor, I believe, did it come from his capital resources … The saddest aspect of your letter is that even at this stage of your life you have not yet understood that that man is your father.''

Lesley and Mervyn were to find out later that, at around this time, her father had transferred his full power of medical and financial attorney to Sophie Mirabella. His married ex-girlfriend, the executor and possible beneficiary of his will, was now to also have sole power over his affairs as he aged and his health declined.

On March 13, 2007, Colin sent a typed letter above his signature, now grown quite childlike, stopping all contact with Mervyn.

"Mervyn, I am not writing to you because I want to,'' Colin wrote.

''No one who has had the misfortune of seeing any of your recent explosions into vindictive hypocrisy would ordinarily risk seeing another. But I am not writing on behalf of myself. I am writing to correct an obvious and indefensible injustice to another … I am, of course, well aware that the task I have set myself is all the more repulsive in that the person who inflicted this cowardly attack [on Sophie] is my son.

''Any further such correspondence to Sophie or me will be ignored. I wish never to hear from you again, on any excuse at all.''

Mervyn was devastated. ''I knew I had gone against his wishes in raising the subject of the contribution to buying Sophie's house,'' he told The Age.

''But the venom in his letter really got to me, it was a devastating thing to read. It wasn't even as if we had hot and cold periods in our relationship over the years - we were always really close.''

Letters over the decade leading up to this point, which The Age has seen, show how out of character this correspondence was. They were warm and loving. In October 2005, for example, Colin had described his ''awe'' at Mervyn's achievements.

''Your personal professional achievement, all done with such a notable and consistent absence of grandstanding … is an extraordinary accomplishment,'' he wrote.

Daughter Lesley said Mervyn had until this point been his father's favourite, the son who could do no wrong.

A series of emails followed Colin's extraordinary letter, during which Mervyn and Lesley tried to extract details from Sophie and Greg Mirabella about their father's financial status and health. Most were either ignored or answered curtly.

But during 2007, it became clear that Colin Howard was not in Melbourne for long stretches. Lesley, who had until then hosted him regularly at her house for dinner, could not find him. His doctor, his neighbours, the people at the milk bar and the restaurant suddenly stopped seeing him. She tried, without success, to contact Sophie and Greg Mirabella, concerned that he had moved to Wangaratta.

"But short of going to Wangaratta and walking around with a placard saying, 'Have you seen this man?', what could I do?"

This was impossible because, in November of that year, Lesley herself had an accident which stopped her travelling.

When she finally did see her father on a trip to Melbourne, he would only say he was staying ''with friends''. He told her he could not tell her where he was ''because he had promised his friends that he wouldn't,'' Lesley said. She asked for a contact number and Colin handed her a sheet with Greg Mirabella's number on it.

Lesley's later attempts to contact her father through the Mirabellas were rebuffed, she said, and, on the one occasion she spoke to him by phone, in May 2008, he said he wanted nothing to do with his past life, then passed the phone to Greg Mirabella.

In September, 2008, though, Sophie Mirabella called her. Colin had had a fall. He was in intensive care in Wangaratta Base hospital, and may not survive the day, she said. Lesley drove up and discovered her father in a coma, concussed, feverish, with a urinary tract infection and a collapsed lower lung.

From conversations with the politician and her husband, Lesley discovered that Colin had been living in a farmhouse on a neighbouring property which they had rented for him, about 400 metres from their house. He was unable to wash himself or clean his teeth, he was incontinent, and fearful that the farm bikes and dogs he heard going past were gangs of bikies come to get him.

Mirabella said her husband, Greg, had been looking after him, visiting him up to four times a day, as she was busy with her parliamentary duties.

Colin recovered from the acute illness, but, while in hospital, was diagnosed with Alzheimer's disease and placed in a nursing home. This seemed to confirm the worst fears Mervyn and Lesley had harboured about their father's mental state and his care in the years leading up to his diagnosis.

In November, Mervyn came from the UK. He had neither seen nor heard from his father since the email of early the previous year. But when he walked into the nursing home with Lesley, Colin was delighted to see him.

''At first he looked at both of us and said, 'I know I didn't want to see you again but I don't remember why','' Mervyn says. ''It was very emotional. He thanked me for finding him.''

It was one of a number of further visits Mervyn paid to his father as he disappeared progressively further into the intricacies of his own mind. But while he could still talk, he described one 2009 visit as "a triumph". On September 2 this year, Colin Howard, QC, died, aged 83.

But for his family, the manner of his becoming ill, the way he became isolated from everyone but the Mirabellas, are still cause for serious questions. They say all they sought from her was reassurance, but she never provided it.

In April 2010, after three years of the family seeking more information, Sophie Mirabella engaged lawyers. She told the family that Colin's financial details, his power of attorney and his will were private matters and she would not tell them any more.

''I have been advised that family members sometimes feel that they have a right to ask about a parent's affairs, but in fact they have no formal legal right to do so,'' she wrote.

''We are very upset with Sophie Mirabella,'' Mervyn Howard said. ''We believe she adopted a deliberate tactic to split our family. And it happened immediately after my father told me that he had made a financial contribution to her by cashing in a super entitlement to help them buy their house in Wangaratta … I feel very badly about that. We did not get to see him; we missed a chunk of the last five years of his life.''

Mervyn and Lesley Howard say they are not interested in their father's money. Both are well enough off not to need it, and if they received any, they would give it to charity. But they do want to be assured that their father was treated with honour and dignity after they were locked out of any decision about his care.

They want to know that Sophie Mirabella, parliamentary pugilist and Tony Abbott's spokeswoman for Innovation, Industry and Science, did the right thing. They will fight this in the courts if they have to, they say, because even now, after their father's death, they still cannot be sure.

Michael Bachelard is a senior writer.