Hi cricker,

I am glad you have found us! First, I want to say - welcome. Dealing with a person with BPD can be both confusing and frustrating, as they process information and emotions differently than the rest of us. And the tools to deal with the situations are often counter-intuitive.
This site had great resources - articles, lessons, workshops, and also just real-time discussions with other members who share their extensive pool of experience. That can all give you the tools to deal with your DIL (daughter-in-law).
I just want to say:

You are a great mom and a mother-in-law, being determined to find the tools for a better communication with her. In the long run, it will have tremendous payoff!
Tell us more about your situation. When did you find out about her possibly having BPD? Have you had a chance to read any books or articles about it yet? Where are you at on your journey of discovery?