Hi. I am so sorry for all of you. This has to be so difficult. When I first read this I was thinking...I don't know how to respond, but the more I thought about it the more I felt inclined to try.
Since it has only been 2 months I would say give it time for the girls parents to somehow come to terms with this horrible tragedy. You might tell your daughter to give them some space right now so they can heal.
I can tell you are a very warm person and I feel for you. I truly feel you are already doing everything you can possibly do for your daughter. I know that might not be what you want to hear, but I believe getting her into therapy where she can vent her feelings is a good thing. I feel that you too might benefit from seeing someone professionally because you seem to be carrying so much pain as well.
I am also a very spiritual person and I agree that this was in God's plan. Sometimes when something tragic like this happens we all find ourselves questioning...now wait a minute...this just can't be. He works in mysterious ways and we are not supposed to understand ...only to trust it. That is a HARD thing to do.
Your daughter will be okay. It will take time for her to heal, but her therapist can help her to realize that it wasn't her fault, etc. I am equally concerned for you because I feel you have no one to talk to and YOU need someone as well. Just give it some thought. If you are having feelings come up that make you even think for a second about "giving up" then you too are suffering.
I know that I didn't say much, but I want you to know this was all heartfelt and I said it all with the best intentions. I hope some small part of this has helped you. Don't be hard on yourself, ok? You are doing a good job getting your daughter the help she needs.
Good luck to you and your family. I will say a prayer for you.
Jeannie