I am sole caregiver for my 87 yr old mother who has dementia. My brother lives 2 hours away and visited last in January. My sister lives in the same town and visited last at Christmas. They both don't want to see mom get worse and are extremely uncomfortable around her when they visit.They talk non stop and very loud and she gets agitated. She doesn't ask about them or mention them at anytime. She doesn't know anyone anymore and wouldn't remember them if they came. I just want to call them and tell if they don't want to come on Mother's Day, they don't have to. I don't know !!
I wouldn't discourage them from coming, but set some ground rules. Tell them to keep the visit short and keep their voices down. If they overstay and mom is getting agitated could mom retire to another part of the house or to her room for a "nap"? If they have a problem with that too bad, it's time they face the realities of her condition and your world.
If they come you can give them 'guidelines for the visit. I've noticed Mom gets upset with loud talking so I find I do better in a soft voice. Dementia is a strange disease. The patient can be spot on one minute and lost the next. Give them all the benefit of the doubt .
As it is, it sounds as if the visits are simply disruptive and do nothing for your mother's quality of life. And, by the way, are a flipping pain in the neck for you.
But if your brother and sister could educate themselves about dementia care needs, do you think it would be possible for your mother to gain anything from seeing them then? What could you ask them to change that would make their visits worthwhile?
The only difficulty I see from your point of view is that, if you tell them (even nicely) not to bother to come, *when* they regret not having made more effort with their mother they will blame you for shutting them out. People who feel guilty like to disperse blame, you know, and you'll be a sitting duck of a target.