Instead of telling him about the technical capabilities of the phone you should just try to boost his confidence and tell him that bullying in no way means you

Instead of telling him about the technical capabilities of the phone you should just try to boost his confidence and tell him that bullying in no way means you are a bad person or deserve the bullying. He might get or feel bullied over other things. The iPhone might just be the thing that you as a parent can help him with, just by throwing money at the problem. Not all bullying can be solved with money, it just happens to be the case here.