No disrespect intended, FN, but for that young man in Canada, all roiled up with adolescent hormones, peer pressure, ect, life is all ahead, while for many of us, it's half, or more, past.
I've five grandsons, all who have heard nearly the same sentiments I voiced a couple of days ago, here.
Having done/made/experienced a lot of stupidity/stupid choices, I would choose to spend the rest of my life in a more constructive manner, helping those I encounter not to make as many poor decisions, and do as many stupid things, as did I.
Don't know a lot about Canada, but I suspect that if 13 takes the offence, and goes 'hunting' his tormentors, he gets charged with a misdemeanor; If he does it well, and inflicts significant damage, the price may rise to felony level. That's the way it worked when I was his age, and now, where I live.
An assault beef would cost him a lot now, and for a long time; If there's a gentler way, we all need to consider that, first. If not, then ya do whatcha gotta do, but with poise and a plan.
Again, FN, I meant no disrespect to you, nor to the young man asking for advice.
Don't start no s**t and there won't be none, Terry