The boy had given evidence that about an hour before the crash his father's eyes were closing and his head was nodding as he drove. He handed his father an energy drink and suggested "they all should have a sleep" before the boy retired to a bunk in the back of the van and napped.
The boy woke briefly "in a town that seemed to have quite a few drunk people in it", the court was told, before waking again when the van was no longer moving.
The court heard Mr Simon had lost control of the van, which had crossed the left hand fog line and travelled down the soft shoulder before colliding with a bank near the Mt Bruce summit on State Highway 2. The impact threw Mr Simon through the windscreen and on to the road.
The vehicle then crossed and recrossed the road while driverless, leaving a trail of debris from its interior, before coming to rest.
First to the crash scene were four members of the Mongrel Mob who turned off the van engine and called emergency services.
Police discovered the boy still inside the van and he was taken to hospital with minor scratches.
Mr Simon had convictions for assault, possession of cannabis and LSD, and domestic violence, most involving the mother of his son, the court had heard.
A toxicology report showed there was no alcohol in Mr Simon's system but there was evidence of possible methamphetamine, MDMA and cannabis use.
