Some people feel sad when someone dies out of misguided and often subconscious selfishness to keep them around. Be happy that you got to know her, spend quality time with her, and let her pass with dignity. The Jewish faith has a pretty good outlook on death, admiring the accomplishments during life rather than the loss during death. Personally, I would rather die before reaching the point where I could no longer take care of myself. Quality of life thing. A few here may prefer me to die quicker, however.