@robmjarrett,
Well, we can't really give you references but I would suggest talking to her current physicians.
Also, this cannot be the first time they have ever dealt with a difficult/questionably competent patient. At some point, you could suggest the family (if you are not in that position) go to court and declare the patient incompetent and incapable of making her own decisions. Not fun, for sure, but the big picture is to assure the patient receives proper care. The smaller picture is for you to not have to suffer from a questionably competent patient's impaired decision-making process.