If it was felt that he has struggled lately with that job, organising the school or counselling the students, he might have been relieved of that responsibility.
I've seen capable men just get old and tired, and their responsibilities become harder and harder to fulfill.
Maybe it was for this reason, in which case he should try to see it as a relief, though I can understand how he would feel like it is a demotion.
Remind him how the CO's are dropped once they reach 70, or bethelites are retired from bethel when they reach a certain point. This might show him that it is an organisational procedure and he shouldn't take it personally.