Can my father legally take a $101,000 home equity mortgage against my father's house when he's not even on the deed?

My father passed away and I found out my brother had taken a 101,000 dollar open ended home equity mortgage line against my father's house. A while back my father and I went to do the same to help me out on some school debt and we were told that the only way ever would be if I was on the deed. My brother is not on the deed and never was! My father's name is not on the loan in any way. Not even co signer! But it's his equity. Everything is my brother. His SS # mailed to him comes in his name etc. The Court house has a document of the loan with my fathers name with my brothers address. I'm trying to take over my fathers home an my brother expects me to pay off his loan. I am administrator of my father's estate and the bank will not even talk to me about the loan. I can't add it to probate because it's not in my father's name. Is this legal? The women at the bank has no idea how that was possible and had to look into it. Then they call me and said it's legal, your father said it was okay. My brother is a scam artist and a very good one. I would not be surprised if he falsified the paperwork. The entire thing just sounds shady! I don't have a lot of money and I'm just looking for some help.