When my sister and I each successively divorced with children our mother opened her home to us with our children. She traveled quite a bit professionally, so she was not there.
Now, in her time of need, we cannot reciprocate, because she is so very difficult. I feel terrible terrible guilt about this and not sure I can ever reconcile. Whether your mother or father, how do you if in same boat? I don't know I will ever NOT feel guilty about. How have you handled these feelings?
The situation when she was younger and you and your sis were in need is totally different. You are comparing apples and oranges. It doesn't work, They are n't the same. Your mum was away and generously let you use her home, Caregiving a difficult dementia patient in your home is totally different. Please let yourself off the hook! You are doing nothing wrong.