I would terminate now. First your child is being violently acted in her own home. I place that is supposed to be safe. 2nd you will loss client's if he does this to other children. Your other clients might also go a step farther after terminating care and call CAS or the police, since you allow their child to be in an unsafe environment. I know as a parent I would make the call if my child came home from daycare with a chuck missing from her face (or elsewhere on her body). This child is a liability to your business and a safety threat.

Yes, you could keep this child close and work with him. But that will take a lot of your attention away from your other children and could cause you lots of unnecessary stress

At the end of the day its up to you if you want to terminate or work with the child. Personally I wouldn't take the risk of keeping him in my care.