The Ending SPOILER

He wasn't a trained teacher, he mocked the counsellor in front of the kids, they didn't put him through any kind of screening to check whether it was safe to even let him work with young children and (working with seemingly the most well-behaved class ever) he hit a child round the back of the head. Also when a child said he didn't like to be hugged, that teacher's immediate reaction was to hug the child and run his fingers through the boy's hair.

He should never have had the job and it's remarkable that he lasted as long as he did.

It was sad but he could go back to college and get his degree and become a real teacher. Or he could become a tutor he was a good teacher.