How to convince preteen son he doesn't need to fight boys who say lewd things about me.

Son is nine and in fourth grade so not quite a tween but not an itty bitty kid either. He takes the bus from one point in town to school and back. Yesterday another child was saying some nasty stuff along the lines if "I fucked your mom" and he lost it. Yelled and cursed at the boy and hit him.So now my kid is suspended from the bus for three days and no amount of me telling him that it doesn't matter what someone says about me will convince him that it isn't worth fighting over.I think it's a guy thing. Not sure if there's a different approach to take instead. via /r/Parenting http://ift.tt/2eZu92l