If the person was only a rebbe for five years presumably he is young enough to move on to another job. If he is older than that and burnt out that is a different story.
I know of one Yeshiva that tried to fire many of their rebbeim. The younger ones moved on. The older ones brought them to a Din Torah. The school lost the Din Torah. Among the things the Dayan told them was a very important point: If it would be so easy to fire a long term rebbe because someone younger can do a better job after a while no one will go into chinuch anymore.