Please help! I really don’t know what to do! Anyone have thoughts about this?

Both of my parents are still alive. My father is 80, my mother is 81. My father suffers from dementia and is getting worse. My mother survived cancer and is very self sufficient. She will need a hip replacement fairly soon. My parents have been divorced for over 30 years. It was a very nasty divorce with my father cheating on my mother and eventually remarrying and starting a whole new family. My father, at the time of the divorce, was completely entranced with his new girlfriend and focused on her primarily. He and this new girlfriend were married for about 20 years before divorcing. My family’s history is very complex and dysfunctional. My mother has supported my brother, who is two years older than me, for much of his life. She has made one bad decision after another (e.g, agreeing to take care of his young child while he moved out of state with a girlfriend and her daughters, giving him money to the tune of at least $150-200,000 for a lawyer to fight a child sexual abuse charge from his wife (mother of his child) and subsequently suing the city for false arrest, helping him buy a house, etc). However, there have been times in my life where my husband and I could have really used some financial assistance and my mother told us she had “no money.” Currently, my brother has moved back to the same state as myself and my parents after being charged with two counts of inappropriate sexual abuse of one of his ex-girlfriend’s daughters. He is currently out on bail. My mother and father have both supported my brother with the financial strains of bailing him out of jail ($5,000) and paying for a lawyer. My brother has vehemently denied the sex abuse accusations. I have cautioned my parents numerous times about giving more money to my brother, who treats them horribly. My brother has not held a paying job for at least 10 years, even though he has many skills and could work. My mother gets extremely angry if I even suggest that my brother might be guilty of this newest abuse charge (he’s been accused 3 times now over the years but nothing has ever been proved) and does not want me to share my opinions about my brother with her. To top things off, all three of these people-mom, dad, and my brother- live in the same apartment building. I’m at my wits end with all of them. My mother and father refuse to face the reality that their son may indeed be guilty and belongs in jail. Neither of them take any of my advice and my mom gets extremely defensive if I warn her not to get involved in various dubious activities for my brother (eg lending my brother her phone to use to make various phone calls even though he has his own phone). He has also involved my mother in housing fraud. My brother is very manipulative and can convince my mother to pretty much do anything for him. My mother’s acquiescence in going along with my brother’s various schemes and bad ideas has long been a bone of contention between us. I don’t know what to do. I don’t really want to see any of these people anymore, they have caused me so much distress over the years. I have a wonderful little family of my own and have been married for 26 years. My husband has patiently put up with his in-laws but he has run out of patience. My dilemma is that my parents are both elderly and I feel guilty about distancing myself from them. Not sure what to do...sorry this is so long...