mad at me for something I didn't do?

so me and this guy we're talking, we're friends. well last night we all got drunk and my best friend texts him saying let's chill he flips out, she tells him she's joking and then he tells her he doesn't deal with high school bs and to tell me he's done and peace pretty much. I texted him today saying sorry and everything else but all he does it read my texts and that's it...what should I do? and why would he be mad at me for her doing?