Don’t be the messenger between two friends who are fighting. Messengers get blamed by both.

Carrying words between two people makes you responsible for things you did not say. Tone gets lost, you soften one line and sharpen another without meaning to, and each of them ends up holding a version of the other that came through you. When it goes badly, you are the one both of them can be angry at for free.

Decline the job kindly and plainly. You are not going to pass messages, though you will happily be in the room if they want to talk. Then stay out of the details, because being the person who refused to relay anything is how you keep both friendships.