Brother pissed off

My one brother is pissed off cuz our other brother is being home this weekend a new gf. He was supposed to be married to another woman she found out he was cheating and called off the wedding which was supposed to be September 2024. He hasn’t told us anything about how his engagement ended only his ex fiancée told us how things ended. We’re not sure if this new gf is someone else or the one my brother cheated with. The brother that’s pissed off says he is going to hate her and calls her a slut. I told him we don’t know everything. You cant judge someone you haven’t met or known.