Goodness! My dear man, you are really going through too much. I have no medical training at all, so am not qualified to say anything, but it sounds so much like dealing with a child that I think I would be tempted to do just that.....I think I'd have the potency of any drugs cut if the docs agree...or put placebos in the bottles if you think she is taking meds for the sympathy.
I don't know how old she is or how difficult her life has been. I know my father-in-law just seemed to decide one day that fighting illness was too much effort, and he just quit. It was hard to watch, but there was no interfering with his 'death-wish.'
It would seem that she is craving the attention. I have to say that at times I was aware that during recovery, my husband was milking as much attention and sympathy as he could from whomever he could. During the rough parts of treatment and the initial recovery, I was at his beck and call and 100% of my attention was on him. As I saw him getting better, I began to back off.....and boy, did I see him suddenly be "unwell" or "weak" or whatever.......and I realized he was just so used to being the center of attention that he was having withdrawal pains! It made me think of raising the kids and I definitely had to wean him away from 'being needy' 24/7. It was not easy, but he surely did need the kick in the pants. The other REALLY BIG kick in the butt came when I was so very tired of his constant complaints about the eating issue. He wanted the feeding tube out, but he just wouldn't really WORK on eating enough to make that happen. Nothing I said, of course, was encouraging enough. The really nice girl at the nutrition center, however, told him the same things I did, and VOILA!, he began doing JUST WHAT I'D BENN SAYING, and within 3 weeks, the tube was OUT and he's been doing well ever since. He admits he needed the Kick from her (mine was just the nagging wife input! )..and perhaps that is what your mom needs....someone ELSE to tell her she is on her own.
The 'thriving at the hospital' comment makes me feel that that is exactly what is happening. She is loving all the attention as is afraid that if she is well, she won't have it.

Didier, I'll be thinking of you and your family during prayers....what a hard place to be in. Hope things improve soon.
God love you.
Nicki