Counsel the teacher and keep an eye out for retaliation

There is no requirement to stay within the school chain, never has been. Here is an unrelated case of why going outside can be a better approach: http://www.photographyisnotacrime.com/2013/02/27/california-high-school-principal-orders-student-to-delete-video-of-teacher-stealing/

All public employees should conduct themselves with a view to what is called the Washington Post test (what if this was featured on the front page of the Washington Post). I always tried to.