While the beneficiary was the last one of five to be sentenced, he was the first to attack the victim whom he spotted as he drove along Moray Pl on July 7.
Boyes parked and immediately confronted the pedestrian, calling him a "rapist" and "child molester".
They discovered the man's name and googled it to verify sex offending claims, finding that in 2013 he was jailed for nearly five years for sexually abusing a young girl.
Two of them joined the melee and again overwhelmed the man, knocking him down. All five surrounded him.
Boyes was joined by Alex Layton Murphy-Fox, Chance John Edwards, Caleb Edward Ross Stefani and Matthew Robert Johnston. They held the victim while Boyes laid into him. He eventually relented and the other men took over until the man was left unconscious on the ground. Boyes drove off.
The victim suffered a laceration to his head and a fractured neck vertebra.
He was discharged from hospital but later readmitted for seizures and headaches.
Judge Turner imposed 10 months' home detention and remitted more than $3000 of fines Boyes had racked up. He did not impose community work because the defendant had "health issues".
Murphy-Fox was jailed for two years two months at sentencing in October last year, during which Judge Kevin Phillips called it "a violent attack ... creating mayhem, disorder and serious injury".
Johnston got seven months' home detention and 270 hours' community work; Edwards seven months' home detention and 190 hours' community work and Stefani 220 hours' community work and 18 months' intensive supervision.