Kat! Omg, I am so sorry you are going through this. I can't imagine the shock you must have had when you received that phone call. That being her "punishment" must mean he wants to work this out.
When it happens to our kids, we take a bigger hit. Do you think it is in your son's best interest to work this out?
Maybe this is a time for them to both realize they have lots of stuff to work out before they take this any further and they will concentrate on getting their lives sorted.
I'm sorry you are your son are going through this. I hope everything works out for the best.