Step son got expelled the last week of school

My step son is now expelled from his school. We have had a lot of issues with him. He does drugs, he gets into fights, he disrespects us constantly. I'm pregnant and it's been stressful. He was being sexually abused at his mothers house for years and at one point ended up in the hospital because he was raped so violently. We've also had issues with him self harming. His dad doesn't believe in therapy and thinks it's a scam but I think he's starting to come around to AT LEAST making his son go to a minor rehab program because he's high and drunk all the time! He took a bottles of vodka and walked into the middle of the street in hopes of getting hit by a car. I'm pregnant so this has caused me a lot of stress. He got expelled for trying to drown one of his classmates in a toilet. His classmate was making jokes about raping a baby. My step son is very sensitive when it comes to children. I can say he loves children and if he got the proper help would be an amazing big brother. He had already earlier this year got into a fight with a guy who was showing pictures of his little sisters developing breasts. After the guy made that joke about raping a baby, my step son followed him into the bathroom and tried to drown him in the toilet. I will say the joke he said was disgusting and made me suck but he can't go around drowning people so now we have to find him a new school...