Povey was driving his family, including three young children, home from a tangi at Otamatea, near Wanganui, when, after six hours at the wheel, he fell asleep less than half an hour from home at Auckland's South Head. The car veered off the road on State Highway 16, before hitting a tree and landing on its roof.
Their son Paikea - a twin - was taken to Starship Hospital in a critical condition and put on life support but eight days later, doctors decided to turn off his oxygen.
Carol said the family were considering going online and buying a star to name after Paikea. She said it was still too early to think about unveiling a headstone for her son.
"In [Maori] culture, it's different for a child. Once the unveiling is done, that's it, it's all sealed - and we're not ready for that yet."
Carol revealed she too was asleep at the time of the crash and had no idea where she was or what had occurred as she stood amid the carnage.
She said the family was relieved to close a chapter in their grieving process.
"Someone had to pay the price and I'm glad it is over because it could have been a lot worse and a lot longer," Carol said.
"[Paikea's twin brother] Franklyn is always calling out to Paikea and, even me, during the times when I'm down and really emotional, he has to see that and that is going to be his lifetime sentence."
She said she wanted a hospital review over the care of her son who, she believed, could have survived.
Povey was supported in court by 29 whanau members who let out a sigh of relief when he was released by the judge.
Judge Chris Field described the accident as a tragic event.
"I acknowledge the presence of the whanau and extend the court's condolences," Field said.
Prosecutor Trevor Beggs said no punitive damages were sought because "he had been punished enough".
Auckland District Health Board spokeswoman Brooke Donovan said no complaint had been received and no investigations were under way.
"We are open to receiving any questions about the care provided and would encourage the Povey family to contact us."