Should I repeat the comments a mutual friend made about another friend's gf.
Do you know where the info really came from?
Yes, I understand my friend's experience. Now, repeating them will ruin the friendship with the mutual friend
Gossip can turn to hostility or manipulation and quickly trigger anger, shame, and resentment. Take  responsibility for your own thoughts and actions, and let other people take responsibility for their own thoughts and actions.
Maybe I don't know. Maybe I am talking to close friends who are not affected by it. I get why the gf can be mad but the people around us can't care.
This sounds like a sensitive situation, and you really don't want to make it worse by gossiping about your friends. You might want to just stay out of the drama altogether and refuse to talk about it. Spreading rumors will only keep it going longer.