Perhaps you might consider that your mother may be considering her choice as a form of escape? The ability to be able to do something different from her daily chores might be a welcome relief and it might just happily tie in with other care that your father is able to receive. It may not tie in with what your mother was able to offer you at a similar point in your life, but that is just simply the way life happens. For the record, my darling ma is in her nineties, but still likes to be 'at home' when the children return from school, to provide drinks, food and an ear.