Hi, going back many years ago ( When we had gas lamps LOL) I had the same problem but with two lads, they used to steal my sweets, playground bully me, taunt me, although my friends never left me because of their bullying, It come to the point where I had enough there was only one way to go & that was was to flatten them on separate occasions maybe not the right way but it bloody well worked I got six of the best for it but was never bothered again, I hope your son the best but that is the only way to sort this out.