When the men went to rescue the back seat passengers - and elderly man, another child, and a trapped woman - the fire reignited.
"That's when it started to get really nerve racking," Buddy said. "It was really intense. We believed the old man was dead ... We had to get him out of the way to get the boy. That was more important, to preserve the other life. "I reached in and grabbed the last person, the mum, and yanked her out and just ran. Then the car just exploded. We were just in time."
Buddy spent about 30 minutes doing CPR but could not revive the man. The rest of the family was taken to hospital.
"Would I do it again? Oh yeah, over and over."
Athenree fire chief and Buddy's father, Peter Harwood, said could not be prouder of his boy.
Mr Harwood said he was yet to speak to his son since the crash but had managed to message a couple of times.
"We're just waiting for the dust to settle before we have a good yarn."
Buddy and Ms Saxton are now being celebrated in Canadian press as "good samaritans who saved a family".
"It's nice to know that your kids, when faced with something like that, they step up," Mr Harwood said.
Lorna Harwood said the rescue had made the couple 'terribly proud' of their boy.
"He was the right person in the right place where he needed to be. We are real grateful he was not hurt."
Last year, Buddy featured in the Bay of Plenty Times after rescuing a woman trapped in her car during heavy flooding near Waihi Beach.
He smashed a window and helped the woman climb out.