Donating a kidney was not something he regretted, Corey Fairbairn said.
"Sometimes I think about it and it is like `. . . I gave away a kidney'. Sometimes there is that moment of reality that I really did that, but it's nothing major.
The end result is what matters."
Dunedin mother Alma McGregor said she still had to pinch herself to believe what Mr Fairburn had done for her son.
Mrs McGregor, who is widowed, would have donated a kidney herself to her son Jason, but neither she nor her daughter were compatible donors and she had "never dreamt in a hundred years" somebody would volunteer.
"What a great person [Mr Fairbairn is].
''It is just amazing how Jason's life has changed, and mine, too."
Her son had been on dialysis for about four years before he had the kidney transplant in July.
The 23-year-old, who is intellectually disabled, had struggled to understand why he had to be hooked up to the dialysis machine for up to five hours a day.
"Life is just so much more enjoyable because I don't have to nag at Jason and say `Come on, you have got to do dialysis'."
Her son's attitude, the way he looked, his energy levels and his humour had all improved following the transplant - even his barber, who sees him only once a month, commented on the huge difference in him.
"He can just be a normal 23-year-old."
Mr McGregor was back at the job he loved in a sheltered workshop and was winning medals with his basketball team just months after the transplant.
For the first time in four years the family can go on holiday and spend four blissful weeks away without having to make any trips back to the hospital.
As the donor, Mr Fairbairn's recovery was not quite so quick and took about six weeks.
His kidney was removed using laparoscopic keyhole surgery, but a wound infection following the surgery slowed down his recovery.
However, as soon as doctors told him he could start exercising again he was back in the gym every day and in December he fulfilled one of his own dreams after he was accepted into the New Zealand Fire Service as a firefighter.
He passed all the physical tests with top marks and starts his 11-week training course this month. He will be stationed in Wellington when he finishes.
Making the decision to donate was something he would recommend to anybody.
As long as someone was prepared to go through with it all, it was a good feeling afterward, he said.
