if you feel the need to put a spell on his bully a binding spell that will turn their negativity back on them and wont back fire on might work
as for fighting back it hard to get away with at shool and that school sounds corrupt so thats a no on that vitims get in more trouble than its worth for self deffence at school unless its after school or away from cameras and such
Put a horse head in the kid's bead, he will never harm your son again!
Seriously, I actually recomend that you take your child to self-defence classes not so that he can pick on the bully or others but so he can defend himself when teh time is right because if he keeps dismissing this child's behaviour it can get extremely ugly for either your side, their side or potentially the laws side.
As a parent, encouraging your child to fight back is not right. If the school authorities are not as responsive as you mentioned them to be. For beginners, injury is very likely if it becomes a brawl and it can lead to your child being lessoned instead, not the other way around. And you will be called due to your approval of the matter, even if it was self defense. Right now, you are in authority to question the response of the school to this matter, since it is the safety of your child we are talking about. Why is that? If violence was to be considered as a common incident which they do not look into seriously, you can question the integrity of the school, and the policies which the school is following or that governs the school. Especially for the security and safety of your child. This isn't the common grounds we are talking about where strangers are walking. It is the ground where people learn to be something more other than immature. This isn't part of learning. What they have experienced in their days isn't something to be tolerated by the new generation since something good has happened as a result. Like them being hell.
Though if self defense is necessary, it must come out of the boy directly. As a parent, do your job fighting the bigger problem = unreasonable people including the parent of the child and comforting your child at the same time. Tell him to be with the company of good people all the time, so people can look after him.
Always remember: It is bad to initiate the problem as a parent, it is wrong. But I understand where you are coming from. In time, your child will learn to fight his own problem, until then. Support him the right way, because if not, it can lead to a different story.
