Hi Mary Agnes,
Welcome to the BPD Family

I'm sorry for what brings you here but know that you aren't alone. We have other parents/grandparents here experiencing something similar to your situation.
Here is a link to another member's thread who is experiencing somthing like you are... .
https://bpdfamily.com/message_board/index.php?topic=331243.0How did you discover BPD? I'm here because my significant other (SO) has an undiagnosed BPD ex-wife (uBPDxw). I discovered BPD by Googling "Chronic Lying"... .and the BPD shoe unfortunately fit.
None of us here can diagnose your Daughter in law (DIL) but her behaviors and the dynamic of their marriage does sound familiar. As you visit with us and read the posts of others you will find we all have an awful lot in common.
You unfortunately have alcoholism added to the mix which is not helpful and complicates things even further.
Your son's lack of contact with you to me could be a couple of things... .one is shame/embarrassment of finding himself in this dysfunctional relationship. I was married to an alcoholic and I tried to hide the dysfunction from my family both to protect them from worrying and because I was embarrassed. The other reason could be that your son's wife is jealous of his relationship with you. Folks with BPD have a lot of black and white thinking. So she can not see that your son can love you
and her, she can only see that he loves you
or her. So to prove to her that he loves her he lessens his contact with you.
What is your contact with your son like these days? Have you been able to talk to him at all about what is going on with his wife? Or does he not feel comfortable talking about it? Has your DIL ever attended Therapy? Have they ever tried Marriage Counseling at all? Are you able to see your granddaughter regularly? How do you feel she is doing?
I would not mention that you have discovered BPD and label your DIL BPD, this will likely put your son & DIL on the defensive. I encourage you to focus on the behaviors, continue to educate yourself. The members here all have someone with BPD/BPD Traits in our lives, there is a lot of support, tools, and strategies that we can share that can help.
Link to more info on BPD in-laws... .
https://bpdfamily.com/message_board/index.php?topic=285794.0I hope to hear more from you about your story and I know other members will chime in soon.
Again Welcome,
Panda39