The phenomenon has to see at the scool when a pupil is marked by the violence. A assistante social have to ask to him if one of parents is violent.
Or always at school, schoolteachers could say to classroom they can to go to the assistante social or call a number phone to help them.
Then if a one have got some domestic violence he knows how to do to help him.
Police could arrest the violent parent or helps him to be better.