Hi and welcome to the board!
I am glad you are reaching out for help and found us. You are in the right place for support from other parents/people who have a loved one with BPD. You are not alone. The other good news is that things can get better over time. We have had families turn things around. We have also had people who have improved their own situations even when their loved one refuses help.
One of the first steps it to take care of you and to learn tools that will help you cope better with what you are dealing with. The tools and strategies we use here can help our pwBPD (person with BPD) but they help us as well.
The eggshells book is good. There are other books that may be more appropriate for your situation. We can better guide you as you share more details. The more details we have the better we can understand and guide you. BTW, we do *not* use real names here as we are very cautious about privacy.
I hope you hang out with us and read and share more.
Again,