That's so sad. I hope something is done to help her.
It is very difficult slimming down a cat who only wants to eat..I have such a cat (Teddy) and however hard I try to keep all the others' food away from him, he always manages to sneak in somehow and demolish all the uneaten food. Of course it doesn't help when you have a dog who can open all the doors in the house quicker than I can and does so whenever she is aware that I am distracted (she, like Teddy (the tubs) is also after devouring all the cat food) e.g. on the telephone etc etc.
The worst of it is that one of my cats, Thomas, has to have lactulose twice a day which I drizzle over his food...but he never finishes his food in one go....too busy dashing about to see who's up for a game...and then Teddy finds it and bingo bongo pegs on the nose for the next few days while the diarrhoea is working its way out of his lardy ar**!
.....Another day in paradise...
Best wishes,
Roz