Davison's three siblings are far flung: gerontologist Mary lives in Australia, biotechnician Fergus in London and teacher Joanna (Jo) Bennett in China. He's estranged from Mary, but Fergus and Jo submitted character references for their brother urging leniency, which were read out in court.
Jo wrote that her mother had asked her to put a pillow over her head, "but I was not as courageous as Sean. I apologised to mum and said that I couldn't help as I had children of my own and didn't want to risk going to prison but, for Sean, mum always came first.
"He suffered the conflict of fulfilling his mother's request against that of his strong humanitarian drive to save life. In the end it was his love for mum which won."
Another petition for leniency came from Archbishop Desmond Tutu. Until this year the anti-apartheid hero was Chancellor of the University of the Western Cape, where Davison lectures in biotechnology and runs a forensic DNA lab. The two had met at university functions.
Tutu wrote that Davison's case "is an exceptional and tragic one", noting Davison's lab identified the remains of anti-apartheid activists whose mass graves were revealed during the Truth and Reconciliation Commission hearings that Tutu chaired.
Davison's lawyer, Roger Laybourn, said if Davison was spared a jail sentence he would lend his forensic expertise to help identify the Pike River miners should their bodies be recovered.
Davison's lab can DNA-profile people from their mitochondrial DNA, the last remaining DNA from degraded skeletal material. Davison has also offered forensic expertise to the Innocence Project of New Zealand, which investigates possible cases of wrongful conviction.
Listening to each side present its case to Justice Christine French, Davison was surprised to find himself wanting to cry. To staunch the tears, he reminded himself of his wife's words. "She said if the word inciting' goes from the charge, this is a badge of honour."
"Inciting" gave the false impression that he had encouraged his mother to commit suicide. In reality, he had initially resisted her pleas to help end her life when she no longer had the physical strength to do so, incapacitated by advanced cancer and a 35-day hunger strike that was her first suicide attempt. He had asked the judge to amend the count against him to remove the word, as it would unfairly taint his integrity and undermine his forensic justice work.
Davison was hugely relieved when Justice French allowed the Crown to withdraw the inciting count and for Davison to plead guilty to a replacement count of "counselling". He considers this still misleading, but less "horrendous" than inciting.
"I found myself in the situation where I had to plead guilty to something I didn't do in fear of being found guilty of something I didn't do. That's incredibly unjust. But I can live with the [new] charge."
He felt sick though, when Justice French delivered her sentence: five months' home detention at a friend's house in Dunedin. He later realised the sentence was very lenient, but the fact remains that the "home" he's being detained in is thousands of kilometres from his real home.
"I think of Raine and the kids because I may as well be in jail as far as they're concerned."
And he's still appalled that what for him was an act of love has made him a criminal.
Sean Davison, 50-year-old New Zealand-born scientist, partner, father, believer in innate human goodness, exercise-junkie and ballroom dancer, never wanted to be Sean Davison, euthanasia martyr. He is too reasoned, too pragmatic for that.
He knows people's memories are short: the personal suffering of euthanasia martyrs (think Leslie Martin, Ian Crutchely) outweighs the shift in public sentiment. Still, he is hopeful his story will nudge New Zealand closer to the legalisation of some form of controlled euthanasia, a law change he sees as inevitable.
I first spoke to Davison in 2009 for three stories I wrote about him. The first two reported on his memoir, Before We Say Goodbye, adapted from his diary entries recounting the final months of Patricia's life, and on Davison's campaigning for the legalisation of physician-assisted euthanasia while he was in New Zealand for the book launch.
The memoir conveys the extraordinarily close intellectual and affectionate bond he held with his mother, a retired GP and psychiatrist who was literary, artistic and strong-minded (her watercolours line the walls of his Cape Town home).
The third story was triggered by a draft manuscript I was posted anonymously. It contained passages cut from the published version in which Davison describes giving his mother a morphine overdose with her blessing. Davison hurriedly left New Zealand after that story, and the next time he returned he was arrested.
In my interactions with Davison, I was struck by his considered candour. He doesn't blurt or pronounce; rather you hear him reflecting aloud, figuring out what he thinks, a scientist inferring from the evidence of his thoughts and emotions. He says his decision to assist his mother's suicide was a moral one.
"I don't believe in God, but I do believe in some kind of judgment, so I do believe you should do what is right. And in the end I did feel I had done what was right."
Raine Pan says he is the gentlest man she has ever met. Pan and Davison met at a ballroom dancing club seven years ago. Pan, who is from China, runs a clothing boutique. She says she is more hardheaded than he. "I make my decision by my head, he follows his heart."
She supported him in his decision to help his mother die, and to plead not guilty to the attempted murder charge. She also wanted him to refuse the alternate charge and leave his fate to the jury's consciences, believing compassion would guide them.
She misses him, but is bracing himself for the likelihood she won't see him for another five months, unless her father gets a permit to return to South Africa from China and holds the fort, including caring for her sick mother, while she visits New Zealand.
Davison finds it too painful to hear his boys in the background when he Skypes Pan. He was separated from his family for three months following his arrest before the court allowed him to return to Cape Town until the trial began.
South Africa has no extradition agreement with New Zealand, and Davison believes character references vouching for him from Desmond Tutu and the Vice-Chancellor of his university helped his case.
His university, which as a non-coloured university under apartheid has a sterling human rights pedigree, has strongly backed Davison and championed the euthanasia cause.
Davison and others close to him now believe the person who sent his uncut manuscript to this newspaper and to Auckland police, effectively dobbing him in, was a family member. He insists he's not bitter. "I'm certainly not vengeful, I don't want to get even. What happened, happened. This person had their reasons. I'm getting on with life."
For the next five months, that means adjusting to the restraints of home detention. He has to apply for leave to go out, and his probation officers have warned him that because he's high profile his movements will be more tightly circumscribed than usual, as someone may recognise him and complain.
He has been on unpaid leave from his university but will now resume supervising post-graduate students and overseeing his lab via internet and Skype. He will also continue discussions with the leaders of the Innocence Project of New Zealand, a joint venture between Victoria and Otago Universities, about how he could contribute.
At present, the project does not have access to the forensic techniques in which his lab specialises. He will also offer these techniques to the identification of the Pike River miners. He grew up in Hokitika, where his father Paddy was superintendent of the Seaview psychiatric hospital and Patricia also worked there.
And he will continue speaking publicly for euthanasia law change. Since his memoir's publication, he has co-founded Dignity SA, which campaigns for improved palliative care and the option of legalised assisted dying.
He received death threats over that - South African police believed they came from Afrikaner religious groups. Partly because of them, he postponed the launch until the weekend before he left for the trial.
But overall, Davison has been heartened by public and media support of him, especially in his adopted home. "In South Africa, public support is overwhelming - they couldn't believe I was being charged with attempted murder. I remember Muslims coming up to me and saying I'm not allowed to say this, this is not in our religion, but I support you'," he says.
"One day they'll look at this case and say this was absolute nonsense: how on Earth could a guy get a conviction for assisting his mother to death at her pleading?"
