In academia, a "sabbatical" means you take some time off from teaching courses, advising students and doing administrative work so you can concentrate on your research. So in order to stay on sabbatical, he'd need to get the AI to do that other stuff.
Not so impractical, don't most undergrads write at a GPT3 level anyways? =)
No, but with a little help I'm sure they could learn to.