You really hit the nail on the head. While he doesn't say they're mean, he does complain about being ignored. People will say hi, ask him general questions about SS or about trips we have planned. Sometimes he's drawn more into the discussions, but sometimes that's it.
He probably is jealous of how happy I can seem around them. He's jealous that I seem to have good relationships with my nephew and nieces, but don't have much connection to SS15. Anyway, I've tried to draw him in to conversations, but it's like trying to push molasses up the hill.
But I think he's also jealous because of what I have. He's shared before that he's always wanted to be part of a loving family. It's not something he's ever had. I'm one of five kids, we're all very close to our parents and (to varying degrees) to each other. I grew up in a town with all four of my grandparents and we saw them multiple times a week. He's expressed feeling inadequate because I know all these old family stories and I know all my grandparents' birthdays. Well, I know because I grew up celebrating them. He loves crime shows and mysteries like I do, but he's also always been drawn to shows about big, loving families. I think he really, really wants to be a part of mine. But he doesn't know how.
I think he could be feeling jealous of your relationships -not like there's anything wrong with what you are doing but the casual and relaxed closeness you have with them.
I can relate in a way, and I don't have BPD. My BPD mother's FOO is a large extended close family- and while they have their "quirks" they aren't as disordered as she is. Even as a child- I wished for a family like that, and to be a part of something like that, but we kids also felt like "outsiders" to them.
Some is them, and some is us- they are mostly focused on their own nuclear family- nice to us but we feel like more of an afterhought than included in their main plans. Even now, they will call when they have time but they are usually busy.
Some is us- we grew up with the shame and secrecy of our disordered family. It's hard to relate to something different, and hard to trust it. CC43 has a point about inviting your family over if you can. There was a time when we lived close by to my mother's FOO and they invited us over but it wasnt reciprocated. We were kids and not aware of it. Years later, my mother's FOO said they thought my parents were snubbing them by not ever inviting them.
On occasion, BPD mother would invite them over and her stress level to have "everything perfect" was high. I think she feared being judged by them, for some reason. It would be a whole day of her stressing and disregulation just to prepare for a visit from anyone really. So it didn't happen often as it was difficult for her.
I think BPD mother was jealous of them too- and wanted what they have. Some of them still live near each other- the adult kids are close, the grandkids are close. What she didn't understand was the reciprocal nature of the relationships they built over time. What she saw was the kids and grandkid's attention to her FOO members and wanted that- but not knowing how to actually foster that. To her, she wanted us to meet her emotional needs, and while we did visit, and do things for her during the visits, this isn't the same as close knit family bonds, built over time.
BPD affects all relationships to some extent. I also think our own FOO relationships play a part. If your parents recently moved- then this is a new experience for him. It may just take some getting used to. Also it may help to have some get togethers with just a few members at a time so that he can relate to people more one on one than the whole crowd at once. That doesn't mean leaving people out of main get togethers but maybe have your parents over for dinner one day, then another time, a sibling and that family- so he isn't navigating all the relationships at once.