Peter Leonard Thomas Stringfellow, 54, was driving with a blood-alcohol level of 217mg - the equivalent of a breath-alcohol reading of between 1050 and 1080 micrograms - when he caused the crash about 3.45pm on December 28, last year.
He was a disqualified driver and three months into a sentence of community detention and intensive supervision imposed on him for a drink-drive offence six months earlier.
He breached that sentence when he consumed alcohol.
Stringfellow, appearing for sentence by audio-visual link in Whangārei District Court, was jailed by Judge Gene Tomlinson for three years, nine months, with a minimum non-parole period of two years, and disqualified from driving for five years.
The court was told Stringfellow was driving his Holden Commodore at speeds of up to 106km/h in a 50km densely populated area in Raumanga, Whangārei, just ahead of the crash.
Despite good driving conditions, Stringfellow lost control of the car on a corner, crossed into the opposite lane, and collided head-on with a Ford Ranger vehicle in which the boy was a passenger.
Police crash experts put Stringfellow's speed on impact at 76km/h. The Ford was shunted off the road and on to the footpath.
Both vehicles were extensively damaged.
Judge Tomlinson said information before the court showed Stringfellow was driving in convoy that night with another vehicle, the driver of which was also intoxicated.
Police noted Stringfellow's comment at the scene, "Well that's the next two years of my life f****d".
Judge Tomlinson said it showed "extreme selfishness". But thankfully - once the full enormity of the harm he caused to the boy and other consequences of his actions had been brought home to him - Stringfellow had since expressed proper and suitable remorse, he said.
Stringfellow himself has a 2-year-old child with significant health issues and realised he had now brought that on someone else.
In a victim impact statement, the boy's mother described the time her son was in hospital as "extremely traumatic" not only for her but for the boy's brother, who was extremely distressed.
It was initially feared the injured boy would not recover from his inability to move one side of his body but he had regained some mobility and was again able to chew food and swallow.
He had since been discharged from intensive care and from a specialist rehabilitation centre.
But he did not get to go home - his mother having lost her job and the house that went with it due to the time she needed to spend at her son's bedside.
The family were now living with her parents and were dependent on the Government and whānau for financial assistance.
The boy's mum said this was the most difficult time of her life and she was in a financial crisis.
She is not sure what the future holds for her son but she is a hopeful person and nurtures her optimism with daily karakia and waiata.
Paediatric rehabilitation medical specialist Dr Jimmy Chong told the court the extent of the boy's injuries would become more apparent over time and will especially take the form of cognitive and behavioural issues that will last long beyond the physical injuries.
The gravity of Stringfellow's offending was grave and his culpability high, the judge said.
The lead charge - aggravated drink-driving causing injury - was punishable by up to five years' jail. While this offence came near to the top of that range, it was not the worst case and the court had to reserve the top sentence range for those.
He set a sentence starting point of three years, six months, uplifting it by 12 months for Stringfellow's previous relevant convictions, and a further six months for the driving while disqualified and breach of intensive supervision offences.
The judge refused to give a full 25 per cent discount for Stringfellow's guilty pleas, reducing it to 20 per cent due to the strength of the overwhelming police case against him. There was a 5 per cent discount for Stringfellow's remorse.
Crown prosecutor Mike Smith urged the judge to impose a minimum non-parole period. Counsel Martin Hislop argued against it, saying it would be a disincentive for Stringfellow to engage with rehabilitative programmes.
Judge Tomlinson said without it Stringfellow would be eligible for parole after 15 months - not enough to hold him accountable, deter others, and protect the community from him.
He disqualified Stringfellow from driving for five years, noting it needed to extend well beyond his release and could be redundant given Stringfellow's past lack of compliance.
The boy's grandmother was in court for the sentencing and was visibly upset throughout.
