I’m my 90-year-old mother’s caregiver with my sister giving me needed breaks. She’s in moderate late stage dementia. She has a few nieces (my older cousins) who have been asking to visit. Never before have they visited her and now have a sudden interest in coming to see her. A few months back one came by and it was an all morning visit that I put an end to as politely as I could. I discussed with my sister that it was too much for my mom and she agreed (as we usually do). It threw my mom off.
Another cousin started calling me. She’s 76 and her 99 year old mom just passed from Alzheimer’s. I thought she was calling me to give me support but she promptly started playing telephone calling everyone and gossiping. I told my sister I was just going to block their calls as it is just added issues, drama and complications I do not need. BTW, I’ve never been close with any of these cousins. They are several years older than me. How would you deal with this?
Even though you've never been close to those cousins, was your Mom close to them? Even though the visit impacts you, the visits are for Mom, right? I'm only bringing this up because if at all possible if your Mom has good history with these cousins, I'd try to have them visit while your Mom is still here. Personally I struggle with whether visits like this benefit someone with advanced dementia... sometimes I think it benefits the visitors more, for a variety of reasons.
Otherwise perhaps you can do a Zoom call with some of them and your mom. I can only guess that they would like to see her once last time before she dies.
The nice thing is that you get to set the ground rules for these visits, so don't be afraid do just that.
Tell them to send flowers, a nice card, or make a video phone call. In person visits are not happening. Do they think they are staying at your house?!?
Once the gossip starts, block them all. They are proving their negative intentions and stupid drama that you don't need.