Just before 9pm, Mr August crossed the centre line and collided with an almost stationary Toyota Prado, driven by Ross Callaghan.
Also in the Prado was Mr Callaghan's partner Tessa Matchitt and their five children aged between 5 months and 14 years.
Mr August was trapped in his ute and died at the scene. Juli was thrown from the vehicle and suffered serious head injuries. He was in an induced coma for four weeks but has since fully recovered.
Mr Callaghan suffered a broken foot and other injuries.
Miss Matchitt and the infant she was holding at the time of the crash, were thrown from the Toyota but did not suffer serious injuries. The other children in the vehicle suffered moderate injuries.
Mr August had 225mg of alcohol per 100ml of blood in his system.
The legal limit is 80mg per 100ml of blood. Traces of THC were also found in his system.
Dr Bain asked Mr Chelley if Juli had been wearing a seatbelt and was told he was not.
"This crash was a shocker really wasn't it? The family that were hit are lucky to be alive."
Dr Bain reserved his finding.