I think you need to talk to her, gently but firmly... that you cannot tolerate this forever. That she needs to take charge of her destiny... be there for her, but do not enable her in her behaviour... she may not be that delusional as you believe... she may or may not... if you are willing to forgive her just because she was "delusional", it's a two edged sword. She may start putting that label on all her behavior that came from mere irresponsibility...

it is a hard situation... but I don't believe that bipolar people are controled by their illness 24/7 and can therefor get away with anything... if it has gone on for so long, in such severity... she shares the blame.