Stepson kicked me intentionally in the 7 month pregnant tum because he wants to kill the baby?

We've had problems with this kid for his whole life. He's in counseling now, and has been for a few months, but it doesn't seem to be going anywhere because she can't get a diagnosis nailed down. We also have a 9 month old girl together, and he's attacked her before because "it's fun to make her cry." So he doesn't get left alone with her at all. But now he's trying to kill my unborn baby because it's a girl and he wants a boy. I just don't know what to do. He screams and pitches 4-5 hour fits and says that we're hurting him and making him bleed. He's up in his room alone during this. He's absolutely DESTROYED his bedroom by peeing on the floor, pooping on it, ripping up the carpet, chewing the paint off the windowsill, and pulling down the drapes so many times we've had to replace the rod and brackets. He tells me that if I spank him he'll tell the police that I punch him in the face and I'll go to jail. He won't stop licking things (like walls, floors, things on the shelves at the market, himself) and then tells me that I just "need to accept that he's going to do it and leave him alone." His bio mom is NOT in the picture, as she hasn't even talked to him since Christmas and hasn't seen him in a year (she lives an hour away from us) It's getting to the point that I just want to pack up my kids and leave, because the situation doesn't seem to be getting better, just worse. I love my husband so much, but his son is completely killing that love to the point that I'm just angry all the time....