students bullying

I have a neighbor whom her son is elementary student and had experienced to be bullied at school. Her son reported to her that his classmates are teasing him and ate his food. The worst thing is while the teacher is teaching, his classmate were all chasing around the room but the teacher had nothing to do. So the neighbor reported to the principal about the incidence and told her if they would not make an action she would transfer her student to the other school. Then the parents were called to talked about the problem. After the meeting she is glad that the problem was solved and her son were not bullied anymore.