Beware, I am treading on thin ice here. You want to look at the Form 1040 Instructions, Page 19. As I read it, you may be able to file as Head of Household and claim your aunt as dependent, if you paid more than half the cost of keeping up a home for her, and if her income, which as I read it may well not include Social Security income if she is poor enough, is less than $2700.

But regarding the tax credit for the disabled, I think this can only be taken by her: see Page 31.