I agree with the previous writer. I would like to add, that maybe your mother has friends, or a senior group that she belongs to. Elder care lawyers and counselors attend such groups, and elders get a one day information session on end of life care. This is done in such a way, and surrounded with like persons, that it is easier to commit to making it better for those left behind.
That is what happened to my mother and I did not have to do the difficult part. I just set up a file for her while she was living and well. I did not have to open it until after she became ill with a stroke and could not take care of herself. If your mother is unwilling to do anything, including see a doctor, you MUST do it for her. It has to be done. However, it takes courage to compassionately ask, "How do you want to die?"
Perhaps, this article can provide some insite. http://www.examiner.com/x-20416-Virginia-Beach-Elder-Care-Examiner