Not sure the right way to handle this but here’s how I’d personally I would approach it. I would take a step back and expect to be included in things and would not pursue my family members so that I could be included. If they don’t act like they are interested, excited, and eager for the prospect of me being a part of it I would consider those actions and behaviors as hurtful, and I would not tolerate hurtful behaviors from anyone.

If your mother (or anyone else) is planning something as the host I would get a date and time from them. If I don’t get that in advance or if they play games, I don’t make it. If anyone asks I say, ‘I didn’t get an invite’, or ‘I didn’t get the invite/plans/location/time until it was too late’.

I wouldn’t have a hard and fast rule regarding how much advance notice I want because I want the flexibility to decide for myself what’s reasonable and this can vary. If everyone is running out for ice cream a half hour might be fine, if it’s a garden party where I need a dress and a gift it’s a few days, you get the idea. Let’s be real, she KNOWS how much time is reasonable so don’t play into her game. Don’t chase her for details, ask once then if you don’t get a reply assume you’ve been uninvited because that’s what she’s doing.

If someone else is planning it or hosting I would not go through anyone else, especially your mother. If she tells you about something talk to that person and don’t follow up with your mother or update her on whether you are going or not. Don’t ask her for details or information, all through the host only. Cut her out of the loop completely. She does not need to be the go between with you and other family members. This is how she tries to maintain control and manipulate you. Manipulation is making someone do something they wouldn’t normally do this situation is manipulation.

If you don’t get invited to your sisters party invite her to grab a sisters birthday lunch together another day. Don’t include your mother. If your sister declines go on with your life and forget about her too.