I am a teacher. Let me give you a few tips on how to work this problem. Go up the chain of command. Start with the principal. Ask for a meeting with the principal individually and then with the teacher (with the principal present). Do not bring hearsay into the conversation. Stay focused on your child only. Teachers and principals cannot, by law, discuss any other students with you, so bringing up other students will go absolutely nowhere.

Go with a list (keep it brief and to the point) of changes you expect to be made so that your son will be treated respectfully and with dignity. If your son is served through special education, you can absolutely ask for an IEP meeting where specific accommodations can be requested, including that teachers only speak privately to your son about concerns (and with care and respect; non-confrontational); calling him out in front of other students can absolutely be prohibited by law through his IEP.

Once you have that in place, if problems continue, move up the chain of command. If you can get these accommodations in place through his IEP, then if the teacher violates the accommodations he is breaking federal law. I don't know about your district, but our district takes those accommodations VERY seriously. Get the special education coordinator involved if the problem continues. PUT EVERYTHING IN WRITING. Your district should also have a list of special education advocates available to parents. Enlist the aid of an advocate if your son's special ed accommodations are not being upheld. Honestly, making this a special ed issue will generally have MUCH more impact than running roughshod over peoples' heads and not going through the chain of command. Special ed violations are serious matters.