Before I say anything further, I want you to know I can understand this situation from both sides. I have suffered depression my whole life and often feel suicidal. I also have a husband with a drinking problem that has the potential to destroy him, and I'm frequently trying to find ways to encourage him to look after himself better.
First question, is she a good mum? Second question, does she work or have any hobbies that get her out of the house?
Suffering mental illness is tiring and draining. For every step forward it often feels like you take 2 steps back. Throw other illnesses on top of that and I can understand why she doesn't want to bother.
Back off on trying to fix her, it's counter-productive. The more you try to fix her the more she's going to act deceptively (hiding candy to ready) You need to let her know you are there for her as she is and if she improves, so much the better. This is a very hard thing to do, I know it. It's an important step because while you try to push her, she'll feel inadequate which will just worsen the problem.
Good luck.
'People are never perfect but love can be. People waste time looking for the perfect lover rather than creating the perfect love' - Princess Leigh-Cheri from Still Life With Woodpecker.