I think you and I have the same mother. I have told her hundreds of times that she needs to move into a retirement community so that she could be with other people her own age and make friends. She would also be walking distance to shopping and would have transportation to the doctor (my husband or I have to take off work to drag her to a doctor's appointment at least once a week because she searches the internet to find things wrong with her---there's nothing physically wrong with her, she just wants to have cancer or something so that we'll all pity her).
Also, she WILL NOT call us--we have to call her. And I always DREAD it, because every conversation starts with her saying, "Well, I guess you're still alive, then." OH MY GOSH!....this woman.
I wish I could offer you some advice but I guess I just want to let you know that you are not alone in this. I wish my mother would see a therapist and get some mental help, but unfortunately that's the ONLY kind of doctor she refuses to see---the kind that she actually needs to be seeing. Ugh, go figure. My brothers do not help me out at all. My mother is driving both my husband and me insane. I really want to just tell her to get out of my life completely but then I would feel guilty. Crazy, I know.
Perhaps your mother and my mother could become facebook friends so they could sit around on the computer chatting all day and complain about how useless and ungrateful their children are.....anything to get her off MY back for awhile!
I feel for you. I really do. I hope that someone on this site has been through this and found a way to set up boundaries. I need the help also!