You are a dear friend for taking care of her. Engaging her in a conversation about what she is thinking and feeling is a good thing....but..
the fact that she's is able to talk to you, to tell you how desperate she is, is something that you need to encourage her to do.

Talking about what your daughters attempt did to you and your family is also good. She should get professional help but I'd tell her that you are always willing to listen to her. I'd also ask her how she plans to kill herself....does she have a plan?

You are my kind of friend Cayokay.