i have a 97 yr old step father, and 89 yr old mother, who both have dementia. they both live in a condo, 3 minutes from me. they have become verbally abusive, paraoid, my mother's behavior is constantly accusing me of things, not true, gets agitated, bangs walls, clenches fists and screams, besides mobility problem. 3 siblings never wanted anything to do with them, but i have now had it. can i turn over poa to one of the siblings even though they do have letters from their primary care that they both have dementia, and are not of sound mind and body. am i stuck with the poa.