I am sorry to read what has happened. I'm glad to read that she saw a doctor and spoke to the police. Is there any way that you can go look at the car and see just how much damage was done?
She called you because she knows that she can trust you....but at some point, she is going to need to tell her family about the accident if they should ask about the car. I hope and pray that this is a wake up call for her and she gets all of the help she needs.
Hope you and the kids are doing okay.
Sit quietly, the answers will reveal themselves when you least expect them to. The past is gone, the present is a gift and you need to focus on today, allow the future to reveal itself when it is ready.