teach the kid how to fight, by whatever means necessary, beat the living shit out of the bully and it will stop. he will get suspended most likely, but he won't live in fear at school or around the kid any more and his confidence will be improved.

or pull him out of the school where he will probably get bullied at the next one, or become less sociable being home schooled, or let the kid continue to be beat up, put down, have things taken from him and he might end up committing suicide or killing someone.