I will be thinking of a good outcome for your son in this, Blue.
My pre-teen and early teen years were the worst. I wasn't an overweight kid, but I was a target. And I wasn't athletic, either. I had 0 backing from teachers and administrators. At one point my dad actually went and talked to a kid's family on my behalf because of the teasing. The family was known by my family. That didn't help, of course.
Even now, when it is clear the bullying isn't just something some kids are "too weak" to ignore, or whatever, Or that bullies aren't just kids who are "jealous" and if you "ignore them" they go away. I think even now people don't get it. The only people who get it were ones who were bullied for real. And, you know, at some point all teachers were kids, too. And you can tell who was bullied, who wasn't, and who was a bully just how they handle a bullying situation. Bullies tend to side with bullies, because they see things in that way.