Is she aware of the diagnosis? It may be frightneing for her but at that same time reassuring to know she's not crazy. Acceptance of her experiences is key. She may feel that what is going on inside of her is strange or shameful. Let her share as much as she is comfortable with and accept it completely. If you have not entered into family counseling, that is a good next step.

I also suggest discussing with her treatment team how the ASD and DID overlap.