I'm really unsure of how this exactly works and it may vary per state. But in reading your post, my first thoughts centered around her state of mind as well as her neglect of her own health. In that, I have to wonder about the idea of having her put in a rest home or some place.
I realize that this may be viewed as a way of controlling her - but my thoughts were more of the fact that she may possibly be a harm to herself and/or others. Is she stable-minded enough to actually live alone (or do you or someone live with her?) Is she actually capable of taking care of herself? (It doesn't really sound to me that she is).
I understand that this may sound like I'm trying to say that putting her in a home or institution of some kind is controlling her, that was not my intent on posting this at all.
I'm not sure if I came across correctly. But I hope that you understand what I am saying. You can't control her drinking, but I"d think that if she is not in her right mind and is a safety risk to herself, you can help her in that manner by providing the care that she needs.
I also agree with the above and believe that your family could really benefit from Alanon and/or counseling of some kind. I truly feel for you all for what you all must be going through.