I work for an Independent Living Center in Kansas. Let me first say that this is a very difficult area to comment on, however my best guess is to contact your local independent living center for assistance.
Some states have respite care programs.
Another idea is to go to Catholic Social Services in your home town. I think that the religious community should be open to helping your mother out. I would also cconsult with a book that no parent should be without in regards to the future. It is called Planning for the Future by L. Mark Russell, JD and others. American Publishing Co. P.O. Box 988, Evanston Ill. 60204.