Seeing as how he died from an overdose I wouldn't doubt if he had been high.
Renfro came from an unstable background. He was a delinquent, probably abused to some degree while growing up with not strong adults in his life most of the time. I don't doubt he could be a bully at that age and disruptive - that goes with the territory. He was a talented person who had a lot of built in demons - sad life.
Ironically, Renfro died not long after starring in the movie "Bully," a true story in which he played a messed-up teen who was being bullied by a sociopathic friend and ended up brutally murdering the friend.
He died 7 years after Bully came out..that's pretty long after. Not seeing any irony anyway. His story has nothing to do with the story in Bully.
So, he was like 12?
Welp...he's dead now. That'll learn him.