If this child is being abused by his parents, it is the parents that are the problem. So the child is seen by a professional, and is told his behavior must change. He tries to change but the parents do not. All he will learn is the professional cannot be trusted.

That said, it is not right that the others be preyed upon by a violent, out-of-control classmate. The child must go if he will not change. Reporting the parents may result in the boy going to a foster home. There still is no guaranty the parents will change. What a tragedy.

Ultimately, the viable answer may mean getting the boy out of the classroom to prevent traumatizing the remainder of the class. The boy is outed for the greater good of the whole.