Hey PurplePenguin, here's what you sent:
Thank you for your reply.
So many things here resonate. Since she was a small child she was very black and white and not afraid to tell you! We just thought oh it’s just because she is a Gemini. Then we emigrated when she was 9 and looking back there have been so many signs. She has a deep fear of abandonment. Super critical yet cannot take criticism. She had an eating disorder in high school. Once she left school we had some wonderful years. Then she met a bad partner and the break up was terrible. But on the day we picked her up she was already messaging another guy. Now they live together(after lots of arguments and her pushing him away) and have 2 small children. We saw them multiple times a week.
This latest and the hardest was in feb. it was her eldest son 2nd birthday and we were due to go to the aquarium. My DH had just been diagnosed with Crohns and was very sick so we couldn’t go.
Well that was it. Fights, screaming matches ect. I thought we moved past it but the relationship changed and was very uncomfortable. Then out of the blue her partner got a job in another state and within 3 weeks they were gone. We messaged daily and FaceTimed and it seemed all was well. Then she started a fight over something we were watching on tv and she wrote us a letter. Well it’s is so bizarre that I have read it twice and I genuinely can’t read it. Basically everything in her life she has had to do herself it was all “I did this/that. And “I never had a safe place/my home was my only safe place” she apparently had her children for me. Her job for me. I pressure her/ don’t get involved with her life. SR called her dad “my partner” ect ect
We haven’t spoken since .. it’s been 3 months and it’s slowly killing us.
Is she like this because I am a people pleaser? She is my last child and I must have spoilt her.. pandered to her? She has always had a stronger personality than me. I worry about her, the babies, her partner. I don’t know how to fix this. I don’t know how to talk to her.
Sorry for the vent. We are just so lost.

and my thoughts:
Hey again! sorry it took me a minute to reply, we had the kids this weekend.
It all just sounds so similar to the stories I've read on the "my child has BPD" board that you're on. The signs since childhood, the inscrutable/blaming messages and letters, not taking responsibility for life choices. It sounds exhausting, especially since your husband is coping with a major illness and you are supporting him.
Asking if you contributed to her condition shows that you want to learn and take whatever responsibility is appropriate -- that's a mindset that will take you far as you learn new ways to have a relationship with her, ways that will protect you and allow both of you to interact in "less worse" ways.
I will say that a mantra I see a lot here is "I didn't cause it, I can't control it, I can't cure it". So many parents arrive asking themselves the exact same question: "What did I do, when did I do it, to make him/her this way". While yes, there is a "nurture" aspect to BPD, there is also a "nature" part. Some kids just get the hand they're dealt, and it's to be hypersensitive and prone to BPD. It's already happened, there wasn't anything you could've done about it. And now that she's an adult, it's her choice how to "control/cure" (manage) her condition and actions.
That doesn't mean there's nothing you can do to change the dynamics between you guys. Are you OK with me posting your message and my reply on the public boards? Can't remember if I mentioned it; I'm mostly on the "coparenting" board because it's my husband's kids' mom who has BPD traits. So I really want for you to get a lot of awesome feedback from parents in your position. Let me know what you're comfortable with.
Hang in there... you're not on this journey alone;
kells76