If he turned around a private high school that was that bad for so long, he can recruit, High schools do a lot of recruiting too, they just have to do it on the down low as its a technical no-no, but everyone does it.
I could be way off base here, but I think I recall hearing that in the particular High School sports conference he was in, they could recruit. I do know for certain that his players were at that school for their brains, not their athletic skill (for the most part) and he got them to turn around their losing trend without a tremendous skill advantage.
He was quoted as saying that he had really bright kids, so he just threw a really complicated offense at them and expected them to learn it. They did, and he had good results.
Now we just have to hope his abilities translate to this level and he can replicate that success.