Hi 3kids1job,
I'm so sorry that you are feeling down, and I can understand that your heart aches for your daughter and family. Seeing our child hurting, and walking on eggshells around a family member can be very stressful and anxiety-producing.
I'm very glad that you reached out for support, because you've found a place with members who understand what you are going through, and tons of resources to help make things better. And things can get better—there is hope!
What ages are your 2 other daughters? Do they all live with you and your husband?
Do you have a support system around you, such as other family, friends, a counselor? It's important to have support for you, so you can stay strong and know that you don't have to do this all alone. There is help out there.
Unfortunately, it's often not easy for someone with BPD to agree to therapy. There can be a lack of self-awareness that makes it difficult for our loved ones to accept that therapy will help them. We have an excellent article on this subject here:
Getting a Loved One with BPD into Therapy I hope you'll find it helpful.
Keep posting and sharing. It helps. We are here to support you.
heartandwhole