Hello Pollyanna7,

I'm sorry your DD has been diagnosed with BPD, but it is great news that SHE is seeking treatment. The fact that she knows she has a problem is more than half the battle. The others here have already told you the evidence-based treatment for BPD is DBT, so I do hope you can help your DD find this type of group setting.
There are peer support groups online for BPD sufferers, but unless those forums are heavily moderated, I shudder to think of the damage they might cause. I'll ask the moderators here if they can recommend any online support for your DD. It might be helpful if there is a site as well-run as this one.
Please let us know how your DD is doing.