Should I get into my parents problems?

My parents have been married for 45 years, but have been separated for 5 years now. My father went to live with another woman who has a child with him. Well, the problem is that my father lives in Mexico and crosses everyday to come over to US to work. He has reached the disability stage and applied for a disability check and all the benefits here, but the property that my mother has is still under his name. Because of that, he is not able to get any benefits. Therefore, he is trying to build a room in their property where my mother has her house and has been paying on her own for the last five years. I talk to both my parents. I love them both. I have only one brother. Today my brother called me telling me that my mother doesn't want my father in her property at all. My brother got into a big argument with my father and told me to stop talking to my father. I clearly told him that I was not going to take any sides that I love both of my parents. My mother is disabled and she has been paying this property with her disability check on her own. My parents are fighting that property like crazy. The only solution I see is divorce. My brother says he is willing to pay that divorce in order for my father to leave my mother alone. Who do you think the divorce will benefit? Should I take a side? Am I a bad daughter for not defending my mother? Should I listen to my brother, I mean we have never been able to get along since he's a perfectionist. Or should I just keep my distance from this problem and continue being with both of my parents?