@Felthry Oh jeez. I'm sorry. Yes, that's an awful place to be.
My experience is that if people have a fight it is over something they care about. You can't change that except by listening as they need and maybe guiding them to ask what they want and whether they're getting it.
You can offer to pass along information, if either party wants.
These are limited tools, sorry to say. Sometimes though they and time will do the job, though.
re: interpersonal -, mh -
@Felthry Unfortunately, yeah, that's extremely hard. Being hurt by someone who didn't even know they were doing it can be worse than being hurt deliberately. At least if you're hit for a reason you can respect that.
If they can decide the other party sincerely regrets it and wants amends, reconciliation might be easy, but there's little you can do there. I'm sorry.
Good luck to you and you all.