You can't do anything short of committing her to a health facility, just recognize that she's doing this for attention, and I hate to say it but don't make her a priority. She knows age gets attention from you and others by getting sick, the less of a big deal you make over her, the less stressed you will be and the more likely it is that she'll realize that her attention-seeking tactics are not working. I understand that this is going to be difficult to do, since its your mom, but really, if she's dying anyway, tough love can't make her health much worse.
F 28/5'4/100 lbs
"I'm not a psychopath, I'm a high-functioning sociopath; do your research."