Women what do I Do ? My son is acting crazy hitting his sister etc. ?

I have 3 children. My youngest son lives with his dad. I live with my older daughter and eldest son. Ages 10,9,5. I have a wonderful boyfriend who is there for me and for my kids. He provides for the, like his own. Does homework with them. Will sit and read bedtime stories with them. He will encourage them to be better citizens all the time, to work hard, respect elders and go to college. I have dated loosers before and that includes my two older children's dad and my youngest sons dad. ,y new bf has a career and great job. My oldest son has defiant disorder. He screams yells, doesn't listen to what I tell him, won't do chores, won't get up in the morning without a fight everyday. Our house is a battle zone all the time coz of him. He hit his sister two weeks ago during an argument. He at times refuses to go to school. The school doesn't have a truancy officer and the police say they can't come to the hse to intimidate him to go to school. He rwfuses to eat my food and says I'm a bad cook and I only cook crap. He kept saying he wants to go live with his dad, whom I kicked out. His dad is living with my sister and her family on their livn room floor. So I drove my son there 3 hrs away. Now his been there a week and me my daughter and bf have had Sooooooo much peace. I love my son though. My son wants to come back now after two weeks living with his dad. Thing is my bf is getting a job in alaska and its paying for him n his family to go. He has told me that he loves ny son very much byt won't put up with the disrespect my sin shows him, me or his siblings and others. my son only wants to come back coz he misses his friends. I fear that if I allow him back from my sisters place where he is staying with his dad we will all just go back to stress. He will defy authority again, insult people, hit his sister, and make our lives a living hell. my daughter loves my bf and its like father daughter releationship. I'm messing her future coz once my son gets back he will make si