Hi!
Is she on medication for these issues?
If so, has she had a recent evaluation with a psychiatrist about the right medication for her? Meds needs to be evaluated for time to time, maybe even several times a year.
Sometimes people who has the wrong meds, wrong combination of meds, will not get better, but possibly worse. Sounds like she is self-medicating...
Is she in any form of theraphy right now?
Keep in mind that it might be a bit of a search to find the right therapist or psychiatrist. Some of them are not knowledgable enough to treat such a complex set of problems. And some therapists and psychiatrists are unprofessional. I can attest to that...
If she is not on meds, or haven't has a recent evaluation, I would make that demand of her, as an ultimatium for you and your husband continuing to help her out.
I would also make the same demand considering going to some form of theraphy / support group etc.
The way I see it, anything else than that, is only going to enable her, and send her even further down an already downwards spiral.
I wish your husband understand that by further enabling her, he is only going to make her life more miserable in the long run.
And lose his wife in the process!
Is couples therapy an option for you and your husband?

It sounds to me that she is too sick to work, and she might stay that way. I am bipolar and I can't work anymore as a resut of that. So don't make demands on her in terms of work right now. That might be completely counterproductive at this point.

Must be so hard for you. Sounds like you have done a lot for her. And had to deal with a lot of hard times as a result of her problems. Sorry that you have to go through this!
Have you had theraphy for yourself? I am such a stickler for going to therapy, because it has been such a life-safer for me.