If the school won't do anything with your friends intitial request, take it to the school board. Throwing a 16 yr old girls type hissy fit won't do anything except alienate your friends and his son.
There is basically two options - move the kid to another school (which would require going to the school board), or go to the school board for help with the principal. The answer is simple, go to the school board and ask them for advice and/or help.
This shite never happened after everyone turned 15 or 16. I never remember anyone getting bullied at my school after like the 6th grade. Everyone pretty much got along. Of course my school was abunch of red necks. No skate boarders