If I can't access my dad's bank accounts, am I still responsible for his bills?

A fellow caregiver asked...

I'm hoping you can advise me. A few years ago, my Father sold his house and moved close to my older brother. At the time, my Father was not in good health and my brother and his wife got him to sign a POA and took care of the sale of the house etc. I live in a different state, and while visiting my Father, he and I went to the bank and at that time my Father and I became aware that my brother had done this. Father was shocked. (now that he was feeling better). My Father went to his attorney and drew up a new Durable POA for me and a Medical POA for my brother. The attorney's letter stated that my brother's POA was still in effect, and when and if it needed to be used, we would have to decide who would be in charge.Then... Father got sick again and had to be hospitalized for a brief time. I traveled to see him. While at my Father's, I went to the bank to get a current bank statement only to find that my POA at the bank had been revoked 3 days before he went into the hospital. The bank would not give me any information because I was not on the account. They would not even tell me if it was done in person, or by mail. Now my brother will not tell me anything financial. He says to trust him. I went to my Father's attorney and asked why I had not been given notice that my POA was revoked, and he said it was not. I do not know if my Brother has gotten a new POA but I was told that if he didn't want to be in charge that the Attorney would be in charge! I had asked the Attorney if an audit can be done. He said, no, not at this time. I have reason to believe that my Brother and his wife owe my Father a lot of money and I think it should be accounted for and a contract made for it's return. I have considered "registering" my POA with the County Clerk because mine is dated after my Brother's (I think)...but if I cannot have access to my Father's accounts...will I be responsible for his bills? Also, my Brother uses the same attorney as my Father...isn't there a conflict of interest here? I'll be traveling there again soon, please advise.