That's an excellent point Lara and I hope she's talking to a counselor at the University.

Koala I can't tell you anything that you don't already know. You cannot be held hostage for her threat...it isn't in your power to prevent her making this choice. And I'd tell her that suicide is not the way to solve problems.
I'd try to "guilt" her about leaving you with this memory ...that isn't how one shows their gratitude for your help.

Remember...no good deed goes unpunished. I love you.