He has not been to his PCP in 4-5 years. I live in a different state than my parents, they are living independently for now. Is more frail, has fallen a few times, but refuses to see a Doctor. I have tried to encourage him to go, my brother lives in same city. I am concerned about his mental soundness. I am not POA.
If your parents are no longer able to live on their own, will they stay in their same city/state or move nearer you? Is your brother actively involved or will he be? My parents moved near me when their need became greater because my brother would never have been willing/able to take the necessary care of them. I lived in the same state, but they had to move 200 miles to be near me.
Also, make sure powers of attorney for both health care and property are in place (or ready to go if they're not done yet). Start researching living wills and what your parents would want if something happens. They may not be willing to discuss these things now, but don't let that stop you from researching different options on your own so that you're ready to step in and pick up the pieces.
You can research places in their town if you think you'll stay there, or look for places near you if you think they might move.