Why Do our Kids Blame Us for their Lives Being in turmoil? Should I Stand my Ground Or Feel Sorry For them?

Our 28 year old son I am sorry to Say is a JERK. He blames me for everything. When he has not been our problem in 10 years. He moved out when he was 18 and been in a home with her every since. It is actually the Girl he is married to that is ruining his life and her older sister.. He met her in 1997 after my mother died. And his life has been in and out of trouble with the COPS. At 15, 16,17 and 18 he was in and out of JDC, for Underage Drinking to Yelling at the teachers at school, to Screaming at me, and Curfew Violtation. To getting her pregnant when she was 15 and he was 16. Thanks to her older sister. He snuck out the bedroom window while I was at work and she took them Parking allowed them to have unprotected Sex and the Girl got pregnant. Then her dad was going to Shoot him. Her parents showed up at our house and I was all to blame. Then 3 weeks later their Fabulous Daughter got stopprd by the Cops with a 13, 14, 15, 2-16 year olds in her Vehicle and she got a $700 dollar fine for Curfew Violation. But if they had searched the car they would have found out she had 22 40 ounce bottles of Beer and several older Bottles of stuff in there with all those kids. He was Barred from seeing them for 6 weeks and he would Lie and tell us he was going to the Park and meet them and take off. But at 20 his wives sister called the Cops on his he got a DWI, and at 21 he got a Public Intox. Then several tickets for Speeding and Careless Driving. Driving without Insurance. But he blames it all on Me. Says it is my fault. Now he is in trouble with DHS. Because her sister lives with them and turns them in for not having feed and having a Dirty House, and Living conditions and 3 adults and 5 kids in a 3 bedroom apartment, But she sits on her BUTT and does nothing. Now our son Got fired from his job and this is Also my Fault when He is the one who had a wreck at work and I find out it is his 5 accident in 8 months. So they fired him.. But it is My fauly because his wife is 8 months pregnant and now they have NO Insurance and When she goes on Maturnity Leave in 4 weeks they will have no place to live. Because her sister and 2 kids live with them and I refuse to let 3 adults and 6 kids move in on My husband. For us to support. Since I am Disabled. And facing Back Surgery. I am Currently Fighting for my Disability. And I have a stress disorder where My nerves will not handle all those kids under my feet. I live in the City Limits and they have an Ordinance where we will be in trouble with the Law for 5 adults and 6 kids in a 4 bedroom house. I Refuse to let it happen So It is my fault because they will be Homeless. I do not see where any of this is my fault. He mad his bed he needs to Lay in it as thee old saying is. But It is all blamed on me.