Hello, Twodognight!
I am glad you have found your way here.
As painful as this break in communication is, I want to encourage you: you can use this silence as an opportunity to heal, build your support systems, and take care of your and your husband's needs. (Hoping he is doing well after surgery?) Coping with a child w/BPD can be exhausting.
And when that first task of taking care of yourself is well under way, you can also add learning as much as you can to be ready when your dd contacts you.
I run conversations through my mind thinking about what I would say to her if and when I ever speak to her again. I know I have a lot of work to do to get to the point where I can talk to her without the conversation going downhill quickly.
That is normal, and your intuition is correct - the conversations would probably go downhill fast, as persons w/BPD require different communicating approach. That type of communication is often counter-intuitive, and that's why we as parents can be of great help, if we learn those communication styles and techniques.
I don't know how she can ever make any progress since she doesn't even know that she has BPD. I know I can't be the one to tell her and she is not likely to ever go for therapy since she had years of therapy growing up.
We as families can actually be helpful in modelling healthy behavior that is effective with pwBPD (persons with BPD) if we get educated in those areas and use them consistently over time. There are of course no guarantees, but there is hope. If you change your part of the dynamic in the relationship, the relationship itself is likely to change as well.
Take it a step at a time, Twodognight, it is a long-distance run... .