Firstly, sorry to hear mate and from the first line, thought you meant your lass had done it as well.

My gf's sister in laws, brother did this. Sounds like a long connection but really isnt when they used to all catch up a few times a year. He was gay and had problems with acceptance. I was really angry at him for it as not only did he take this way out of the problems but did it in his parents house (overdose).

With your lass, I would just be there and definately take her away from it all for a day/afternoon to chat about it. You might get some more info on whats making her tick at the moment. Deep down she will know its not her fault but there are demons fighting that.

Just be with her and tell her how you feel but I would avoid any form of anger towards the guy and just be tolerant. It does get better and well done for posting