J.R.
Because he is in high school, I would honestly discourage you from taking action yourself. You can give your son advice, but don't talk to the friend for him. By that age, they need to learn to dieal with situations on their own. If I were advising your son on this situation, I would tell him that he has three choices: accept the kid as he is, tell the kid that his copy-cat behavior is bothering him, or drop him as a friend... let your son decide where to take it from there.