This is largely a rant, but advice is very welcome.
My mother is very emotionally immature and in my 20s/early 30s I didn't speak to her much. More recently (I'm in my 40s) I decided to accept her as she is, she's mellowed out a lot and we've manage to build a pretty good relationship. We don't live in the same country but we chat fairly often and see each other a few times a year.
She has a big birthday coming up next year, so I've been talking to my sister (who lives in the same country as I) about organising something for that. I've spoken to my mother and asked her if she'd like a party in her town, or if she'd like everyone in the immediate family to go away on a trip. Response was 'oh I don't want a party,' and she was keen a trip, so, trip it is.
The problem is that at a previous significant birthday we were told no parties, then my other sister (who is a horrible being) organised a party without telling me and my (not horrible) sister. There is a 'lovely' photo from that party of all the extended family with me and my sister and our husbands/children excluded. As you can imagine, neither of us was happy about this. My mother said nothing about it because she ignores my horrible sister's behaviour due to aforementioned emotional immaturity.
I can see my horrible sister doing the same thing again - there has already been talk of 'something small' being organised. Or if she doesn't do it, I can see one of my mother's sisters (who are genuinely nice people) organising something low-key and last-minute which means my sister and I won't be invited.
So I have a few options - lovely sister and I organise a party, even though my mother says she doesn't want one, to short-circuit a situation where my horrible sister organises something without us.
Let go of the whole party thing and just do the trip and accept that there will be another extended family photo without me and my lovely sister and our families.
Try to talk to my mother about this. This is the worst option as she is incapable of discussing anything.
I know there's probably no good way out of this. It's surprising me how much it's upsetting me - I think years of accepting low-level crappy behaviour are coming back to haunt me. Thankfully my (not horrible) sister is an angel - without her I'd probably lose my shit entirely.