No therapy, but most kids go one of two ways... they live in fear of the cruel kids constantly or they eventually get to the place where they have those one or two good friends and they decide they are going to just be themselves and to hell with those that don't like them or find them different. Kids that have had to deal with verbal and even physical abuse tend to be much tougher than we think. So if he has found his spot and has the confidence that is a good thing. The key I would think is allowing him to make the decision because he knows his interconnections at school better than you or I.
Yes a case or even a skin would take care of the issue should it become one. Our local Junior High School doesn't allow kids to have phones at school. If you bring one you have to turn it in before the first bell and you can get it back at the end of your last class. If you get caught with it at school, you are suspended for 3 days. Heck of a way to deal with it, but I guess it just became a problem with the kids being on the phones rather than paying attention in class.