I did, and I really enjoyed it! It was not a sustainable financial option for me (I spent far more than I made there due to the employee discount) but was successful in that it gave my life a bit of cadence while I recharged for a few months. I almost did the same thing during my last hiatus, but as a parent I was not inclined/allowed to drift off into endless video game marathons.

My limited/indirect experience on both sides of the "overqualified" thing is that it's usually a result of the employer feeling threatened this person will supplant them, or the prospective employee coming off as entitled or non-serious. Having a doctorate doesn't impinge on your ability to mow lawns, but if you're making sure everyone knows you're meant for better things, that's a problem.

He should write Jail instead of Yale when applying.