The attack happened at his Seaforth Rd home in Bowentown, north of Tauranga, on March 14 while Leroy had been visiting.
A summary of facts stated Tawhiti and his son had a volatile relationship.
About 8.30am on March 14, while Leroy was sleeping inside a cabin on the property, his older brother arrived and was confronted by their father when he saw Leroy's vehicle.
Tawhiti senior yelled at him: "Where the **** is your brother?" Concerned about his father's aggression towards Leroy, the older sibling said he wasn't sure.
Tawhiti senior replied, "Well, there's his ******* car", and told his older son to "**** off."
He then took a petrol container from a nearby shed and approached Leroy and threw petrol over him and used a cigarette lighter to set him on fire.
Leroy's body was engulfed in flames from his shoulders down and he ran into the Bowentown estuary to put the fire out and cool his burns.
His father then made a second attempt to douse his son in petrol but Leroy's brother and sister stopped him. Despite being in significant pain, Leroy confronted his father about what he had done, and a verbal and physical confrontation ensued.
Leroy then drove to his home before his partner drove him to a relative's address where they called 111 and he was flown to Middlemore Hospital.
When interviewed, Tawhiti senior told the police that his son said he was going to kill him.
Crown prosecutor Ella Collis read Leroy's victim impact statement to the court, which stated he still struggled significantly both physically and emotionally over what happened and he had been diagnosed with suffering a post-trauma stress disorder.
"I am still unable to walk and primarily I rely on an electric wheelchair to get around, and can't fish or dive for food, and I have to rely on my partner for everything."
All the medications he had to take also made life "even harder".
Leroy also said he was still angry and "very upset" about what his father had done.
"I still wake up screaming twice a night," he said.
The father-of-three said he and his partner were expecting another child and he was concerned about the physical and mental demands on her and their children.
Leroy said he has had 28 operations and more are scheduled, and at least twice a week he had to visit Tauranga Hospital to get dressings changed. His injuries included some 65 per cent full-thickness burns which will never heal and it was uncertain whether he would regain full mobility, the court heard.
Doctors confirmed that Leroy could have died if he and his siblings had not doused the flames as they did, and if it had not been for his strong physic and mental resilience.
Leroy said he would carry a permanent reminder of what his father did to him for the rest of his life but was determined to be a better man and meet his rehabilitation goals.
Collis suggested the judge consider a sentence of 11 to 12 years before taking into account Tawhiti senior's guilty pleas, remorse and cultural background report.
Tawhiti senior's lawyer Kerry Tustin said 11 years was appropriate given there was a clear causal link between her client's violent and deprived upbringing and his offending.
The court heard Tawhiti senior was a victim of inter-generational abuse including daily beatings by his father growing up. Tawhiti senior wanted to apologise to his son, accepted full responsibility for his actions and made no attempt to shift the blame onto anyone else.
Tawhiti senior wanted his son to know how much he loved him and hoped to be able to apologise in person someday, Tustin said.
Tustin said Tawhiti senior also told the report writer that he was determined to do everything possible to become a better person, a better father and koro.
Tawhiti senior had previous convictions for violence but his last conviction was in 2002 and he had undergone some counselling at that time, the court heard.
Justice Melanie Harland told Tawhiti senior this was "an act of extreme violence" which was premeditated to some degree.
"You did have choices and the opportunity to change your mind, and there was also a second attempt to try and throw more petrol over your son.
"I agree with the Crown that there is an element of premeditation, and of course, igniting an accelerant is the use of a weapon which makes your offending worse."
Harland said she accepted the influence of Tawhiti senior's upbringing but it did not excuse him for reacting in such a "violent and aggressive way".
She said the severe injuries suffered by Leroy understandably had a profound and adverse emotional and physical impact on him that was likely to be lifelong.
"He has been left traumatised and yet he is still determined to meet his recovery goals. I acknowledge your son's bravery and fortitude ... It is nothing short of inspiring."
Harland said she accepted Tawhiti senior's remorse was genuine and also took that into account.
