She doesn't understand why we shuttle her between our separate homes. We are determined to keep her "at home" for as long as possible. Her dementia prevents her from understanding that we take turns caring for her to avoid the inevitable. She is 94, can take care of toileting. She becomes agitated on our transfer days for a few hours. In my heart, I don't think there is an answer just wanted to put it out here
If that's not feasible, then I'd weigh the pros and cons of the matter. Is a facility an option? Would she benefit from what they would have to offer in your area? Would this alleviate the distress she is getting from the transfers between homes? And if she does progress in her dementia, are you and your sister going to be able to provide for her care in your homes? All factors you might consider.
Mom eventually got to a point where she could not be cared for at home. She has been in a nursing home a little over two years now. I am very glad she had that transition period at my sister's, but really, it is so good for her to have daily activities, to be able to get her hair done without leaving the premises, to visit with others her age, to have medical attention right where she is, and to have us come to her instead of disrupting her routines to come to us.
What you are doing probably isn't ideal, but it may very well be the best option for all of you at this time.