Yes, I'm making some progress.
Out of the blue, my uBPDmom announced with five days notice, she wanted me to organize the family get-together for Fathers Day and her birthday (all celebrated together). I said "OK", but then she added a condition: no children. I didn't know what to think at first. It was going to be at her home, so I didn't know how to not respect her wishes.
But how could she expect me to tell my sister and BIL that they couldn't bring my nephew6 and niece4? Since I had a busy week, I put it aside and forgot about it. My wife reminded me later, and I thought about it. We both agreed it was a weird request. I finally said I'm not getting between my uBPDmom and my sister... . that's called triangulation. And of course, I wanted the kids there anyhow.
This seemed to blow over on it's own as uBPDmom said nothing when I sent a group email indicating the kids would be there too. In the future, I'll remember this.
Fast forward to the event, and we're trying to order in some food for everybody. So I was appointed to the task of working with all the preferences and dietary restrictions of 7 adults and 2 children. My BIL wanted a couple of spicy dishes in the mix, and I was happy to oblige his Fathers Day request. This triggered a meltdown by my uBPDmom, directly mainly at me. I froze.
All of a sudden it was all about her. To my surprise, my sister scolded our uBPDmom like she would a toddler. This caused uBPDmom to leave the room in tears. But she soon pulled herself together and came back in. Nobody fell for her act.
Well, I made it through without a nervous breakdown
