"This is as emotional as we've felt since the actual event took place," he told APNZ.
While the legal process was officially over, the Crown confirmed a few days ago it would consider appealing against the High Court decision which saw the 18-year-old attacker go unpunished.
However, it might be weeks before the review was completed.
Mr Dudley said a conviction for the older offender would partially ease the pain but the case had now become bigger than their grieving family.
"It's about not opening up the floodgates for other poor families to go through this," he said.
"We're almost obligated now to go as far as we can with this, not just for ourselves but for New Zealand. This could've been anyone's son or daughter."
In the last week he and his wife Mona had been inundated with offers of legal support from people and organisations willing to look into the case.
Mr Dudley said they would await the Crown's appeal decision before making a decision on any potential private prosecutions.
Brent Dudley delivers his victim impact statement. Photo / Doug Sherring
He confirmed there were several groups who had approached the family but did not want to disclose their identities yet.
"We owe it to Stephen to have a listen to everybody who might have something to offer," Mr Dudley said.
One of those lending a hand was Dermot Nottingham, who lifted the lid on odometer fraud more than a decade ago.
He said he had agreed to write a report for the family after viewing the evidence before the court, and would assess whether there were further legal avenues to pursue.
He was damning of Justice Winkelmann's recent ruling, particularly in her assessment of the post-rugby-practice fight as "schoolyard violence".
"There is no suggestion that any of the blows struck caused injury in and of themselves. Assessed in that light, these were punches thrown in the context of a schoolyard fight. If Stephen had not died because of his undiagnosed heart condition there would be nothing to distinguish this from numerous school yard fights," the judge said.
Mr Nottingham said if that was the case, the school ? the identity of which is suppressed - may be culpable.
"I think the whole thing's a sham," he said.