I was asked to become my mother's 86 yr. olds best friend POA after my mom was told she had cancer (mom passed away). We went to her attorney & got the papers. A year later Loretta had brain surgery. I was taking care of her for months and had her in rehab/nursing facility. She was on the long road to recovery. While there, someone else came by with a notary and told her to agree to have her POA (she wasn't in her right state of mind) would that even be legal?
My understanding: Assuming that the person is mentally competent, they can change their mind and name a new POA by revoking the original POA. This means pulling all filed copies of POAs from whereever they are placed: attorney and doctors offices, hospitals, NHs, banks... When a POA form is placed somewhere, it should be recorded on the POA paperwork with the date, time and initials of the principal. It is not a casual process.You should have received a letter of revocation. If you think that the person was not of sound mind, which it sounds like you do, then reporting the issue to the Agency on Aging in your state would be the first step.
I wonder if the original attorney is around to consult with? Is the attorney still on retainer or has that expired? If still on retainer, you should be able to contact them and get an answer. I hope that this helps and I will be following to see if you get differing viewpoints. Good luck. I hope that you are able to straighten it out for Loretta.