How do you forgive your other relatives when they show their true colors with regard to your ailing parent? I have been truly shocked at the level of withholding and selfishness that I have seen - I feel more grief over this even than my mother's decline. I suddenly feel alone like I have no family I can count on anymore and even worse I will be expected to be the caregiver for the most selfish one of all in the future.
Do you really want to move to care for your mother? It sound like this is really hard for you. Are there other siblings? How about moving your mother near to you?
I read often how family moves to the older persons location. This is not a progressive idea. Life moves forward not backwards. The past is done, the future and future generations is where it is at. Preserve the past, secure the future.