Setting aside all of the good gags in this thread...
Just cut him off, he knew what he did and he's not worth your time at all, and this just shows that if you do continue on with this "friendship" that he'll probably forget you over more and more later on in life, wether it be Relationships, Finances, Property, etc.
this is someone who does not care about your well being, and possibly that of others around him, unless he pours his heart out to you and genuinely apologizes for what occurred just cease to communicate with him. He'll get the memo.
edit: also these people telling you to fight him seem to forget how easy it is to do some serious damage to people in fights, I've been in multiple situations where I've been punched/slapped (yes slapped don't ask kek) and disrespected where I could've beaten the living stuff out of people, yet I just kicked back and accepted it because my actions would've made the situation far worse. I've come to realize that violence really doesn't solve anything unless it's in the defense of personal property or family. Not to mention how easy it is to kill people/cause internal bleeding in fights. Fighting's definitely not worth your time or anyone elses.