just make sure your gf knows your there for her....since your just the boyfriend (no offense please) you really dont have much of a say...but as long as you keep yourself strong and continue to support your gf....and perhaps offer her to go to personal therapy ...also make sure you listen to her...and ask her how she feels...and ask what you can do to make her feel better....i really dont know how old you are...however im sure her mother is not going to well calm down all that much until something happens....tell your gf to sit down with her mother and actually have a conversation with her .....whoever started this mess this pretty messed up...and perhaps your gf should pull this member aside and ask the reasons why it was exposed....it was bound to happen....now your girlfriend just has to handle it properly....good luck and let us know how it goes