Roommate's Mental Health Struggles and Family Cycles of Abuse

So this is a weird thing because it’s not about me exactly. But my roommate recently lost a parent, and had been struggling with mental health even before that. They were one diagnosed w borderline but then another therapist said they didn’t, but have behaviors from a parent who has it. We had a horrible argument the other day and now my roommate hasn’t spoken to me since. During this they yelled, made up accusations, literally said “I won’t act like this if you go (to the event we were arguing about), but I’m just angry” a lot of weird things I know come from their family’s cycles of abuse. What if they really have borderline, either way I am running out of ideas for how to help them or set boundaries to help myself.