Those checks had since been completed and Judge David Robinson imposed four months, three weeks' home detention.
At sentencing, the court heard how Nick McEwan and his family had attended a birthday in September last year and were travelling home from Oamaru to Waitati.
Miller was driving in the opposite direction in an unregistered ute with bald rear tyres, towing a trailer, and had been veering over the centre line for 5km before the collision.
Worst affected by the crash was McEwan's then 3-year-old son who suffered a broken neck and arm, leaving him permanently affected.
The family were helicoptered to hospital with an assortment of broken bones and lacerations.
McEwan recalled the excruciating half hour after the incident, trapped in the car, hoping his loved ones were not too badly injured.
Miller initially blamed the wind for his wayward driving, but a test revealed methamphetamine and methadone in his blood.
It was initially thought that the defendant would be automatically deported if his prison sentence was commuted to home detention.
Yesterday, however, counsel Karlena Lawrence said there were three options and Miller would have appeal rights should he wish to challenge the decision.
Most likely, she said, was "suspended liability" whereby the man would be allowed to remain in New Zealand if he did not commit further offences.
While Oranga Tamariki had some concerns about Miller living with his family, Judge Robinson said the defendant had previously acted as a caregiver for his partner.
Should he breach home detention conditions — which included a ban on drugs, alcohol and driving — re-imprisonment would be inevitable, said the judge.
Miller was previously disqualified from driving for two years.
