Hello Snowcat 84, welcome to the BPD fam.
I am sorry to hear your family has been thru so much!
I do not have experience w/sexual assault, but know it is definitely a trauma that needs specialized care in healing.
There are many treatment centers some good some not so much. You have to do your due diligence, visit etc. Are you in the US? My D16 just completed an 8 month residential program and it helped her tremendously. If you're in the US, do you have a CMO (care manager)? We have one and she was able to guide us / arrange residential visits, etc. We are in NJ and this placement was no cost to us.
Please hang in there and no you have lots of support

BPD fam.
Bright Day Mom