He can't spend time with his daughter without spending an equal, separate amount of time with his mom.
I don't know what it is about BPD that makes their whole world revolve around "keeping score", whether it be an "eye for an eye" narrative (fighting back with their version of an equal amount of pain), or doling out the candy "exactly equally" between the grandkids. Or in your case, ensuring "equal time" is spent with each family member. There is something about BPD and the narrative of "equal". Not saying your H is BPD, but I'll bet his mom is making sure she is "getting her share of her version of equal", and making that known to your H, who lives the world of obligation to keep mama sedate, rather than risking the terrifying guilt parade or another rage.
My mom, who I see once a year and lives 10 hrs away, came to visit us. H told MIL about the visit. She became sad and felt left out. In response, H told me how lonely his mom was, that she wanted to come visit too.
I can relate. My mom lives in my town 6 min away from me. Once a year, my FIL used to come visit and stay for several weeks. He was physically high maintenance (advancing vascular dementia) and pretty much 24/7 care, and my mom just could not seem to handle that he got all the attention whilst he was staying with us (despite the fact that she got all the attention the other 50 weeks of the year). I think when he came, her switch flipped, and the "sense of abandonment" emotion kicked in.
I'm speculating, but I cannot even put into words the time she came to our house with a "mad on", and raged the hurricane from hell. Slammed the back door so hard when she left that the whole flipping house shook. It was her first and only public rage (my H and daughter were present, and I was unable to talk her down by reminding her that her grand-daughter was present). Your H is probably doing what he has to do to prevent this kind of scene because the words that come out of their mouth deliver terrifying and hurtful personal messages designed to inflict as much pain as possible on
us.
His adult daughter and her fiancé came to visit us this past weekend. We had a lot of fun and she posted pics of the weekend on social media. MIL saw the photos and told H that she feels left out. H apologized, then turned around and asked if she could come for Thanksgiving. Wait for it: he assured me that it would only be for the day. He respected the boundary for the very first time.
Oh my PJ. This is a win.
I know you're probably carrying a lot today, too. Find time to put the burdens down. It's ok to laugh. It's ok to really enjoy your life. It's ok to trust your gut. You're a good person and you can do this.
This is an awesome mantra and reminder for all of us. Thanks for this gift.
