I'll agree with you with the caveat that "just a nervous breakdown" might be a little dismissive.

Does he need a sabbatical? Absolutely. It sounds like after one-too-many classes of willfully unteachable students (as in students that refuse to learn, not students that are unable to learn), enough was enough and he had had it with these motherf%$&ing students in this motherf%$&ing school.

I think a lot of us here on HN can empathize with overwork and burnout, and it sounds like this professor may have ignored the warning signs for too long. I hope he can get the help he needs.