In the darkness, the frightened boy, who was himself injured, searched in vain for his dad, before running 6km in socks to seek help at a family friend's house.
Mr Bennett was later found dead about 12 metres from his ute.
In his finding released today, Coroner Richard McElrea ruled that Mr Bennett died of his injuries after being ejected from his ute.
"He was distracted at the time he lost control of the vehicle," the coroner said, after hearing evidence from police crash scene investigator, Senior Constable Simon Burbery.
In his comments/recommendations, Coroner McElrea said Hunter's actions were "very commendable".
But his mother, and Mr Bennett's partner, Emma White said she didn't want her son reminded of the incident.
"He's fine, but Hunter will not be shown that - he doesn't need that sort of stuff brought back up again," she said today from Haast.
The family were living in Queensland when the tragedy happened.
Mr Bennett was working for a mining company in Cannonvale, but had returned to the West Coast with Hunter for a holiday to coincide with the deer mating season, and to pack up the last of their possessions.
They were on their way to catch a flight back to Australia when the crash happened.
The coroner heard evidence that Mr Bennett had been distracted shortly before the smash.
No other cars were involved but it was dark and raining when his ute crossed the centreline and ran on to the grass verge.
Mr Burbery said Mr Bennett travelled about 24m before he reacted in "an alert and appropriate manner", trying to steer back on to the road.
"That is not the typical action of a fatigued driver who would be expected to have a much longer period of situational assessment before reaction," the crash expert said.
"Instead, it would appear the driver was alert, but distracted with some task other than driving."
Coroner McElrea heard evidence that Mr Bennett may have been steering "using his knees", reaching for a cassette or trying to put on his seatbelt before the crash.
