My Brother Named A Mentally Unstable, Abusive “caretaker” As His Medical Poa

My disabled brother and I (both in our 70s) live in different states (I’m in Colorado and he’s in Florida). I am not able to travel due to a medical condition. My brother’s neighbor reached out to me on Facebook and said he has ongoing concerns for my brother’s well being and safety. Neighbor has witnessed my brother’s roommate verbally abusing my brother and locking him out of the house. Neighbor called adult protective services, but doesn’t know if they ever investigated my brother’s living situation. I phoned my brother, but he was unable to answer simple questions or hold a conversation. His roommate took over the call and I expressed my concerns for my brother’s inability to communicate. I mentioned my brother should be evaluated and he might require assisted living. Roommate said my brother is fine and that he is my brother’s caretaker and that my brother named him as his medical power of attorney. Roommate raged and told me my brother wants nothing to do with me (my brother and I have never been close, but have always gotten along fine). I am aware that the roommate is on disability for mental health issues. LEGAL QUESTION: is it within the law for a person with severe mental health issues to be named medical POA? Any advice on getting my brother help would be appreciated.