I think sometimes moving schools is best. You try various solutions (e.g. talking to parentsteachers) for a year or two, and in the meanwhile your kid goes to school every day to be humiliated and laughed at. Would any of us stay at a work place where they call you names and throw things at you?
People say he should learn to cope but sometimes they are just afraid his pride would get hurt by giving in. Well pride isn’t such a great thing anyway.