You should definitely get him checked out medically just to be certain that he is just ahead of the curve.
You said that adults are attacking him? Physically or verbally? What kind of ignoramus adults does your town breed?
Kids always pick on anyone who is different. Clue him in that getting angry (and in physical fights) just gives them the reactions they’re looking for. If he figure out how to keep his cool or ignore them, they’ll likely move on to more satisfying targets.
Try to help him come up with some humorous one-liners when they start up. This will give him a better alternative to fighting.
Point out to him why physical fights will just cause him more problems with teachers and school authorities and won’t change the teasing. That’s what the bully kids want.
You can also point out to him that the majority of our presidents have been tall as well as many leaders of industry. People somehow connect height with leadership qualities, at least subconsciously.
If all else fails, a little time with a good therapist specializing in adopescense can work on his self acceptance and creating a better perception about his height.
It’s not going to change (except to increase) so the sooner he can learn how to be comfortable in his own skin, the better for him.
Physical fighting as a defense mechanism will come back to bite him in the butt at some point. Better he should learn some skills so he can be a happy well adjusted tall guy. There are so many advantages to it. He just needs to focus on that instead of all the ignorant dimwits giving him a hard time about it.