Wish I had some advice for both of you, lefthanded and vligrl.
I went through the exact same thing for a few years and lost my mother to Alzheimer's in December 2010. I was not able to visit her often as we live a great distance away, and because I've been on disability with Chronic Migraines. When I was able to see her, it was very difficult dealing with her not recognizing me. I also suffer from depression and anxiety, and found it very difficult to sit very long with her when she was unable to recognize me. At times she would say things that made no sense, and I was in such a sensitive state, I would begin crying, which I don't think helped anything.
My brother lived nearby and was able to visit her frequently, but I felt that he resented me for not being there more often and for not helping more with her care. We both had power of attorney to handle her medical and financial matters. I was just too ill to do any of it--physically and emotionally.
Anyway, I just wanted to offer my support and encourage to both of you as I know what you're going through.
I was able to spend every day of the last two weeks of my mother's life with her. I honestly don't know whether she recognized me or realized I was with her. She recognized my brother (that was painful for me). My brother and I spent every day with her those last two weeks and the last 3-4 days we spent the nights, as well. I just sat with her, holding her hand, reading her favorite Bible verses (ones she had made note of in her Bible), and singing to her when her pastor visited.
The nursing home where she lived the last 2 years was a memory care home, so they specialized in Alzheimer's patients. One time, the administrator and my mother called me (I was ill and in bed), but my mom started crying partway through the call and repeated, "what did I do wrong?". I was crying, too, then, so I don't know if the phone call was a good idea or not. I still don't know if she understood what was going on or not, and I don't know what she meant. It was very difficult.
Hang in there.