He's not and that's why he's here.
Had to edit this to add: I didn't say what I said above because I think he sucks as I don't know. He isn't far removed from being a high school head coach and collegiate as well as the NFL is about who you know as much as it is about ability. Don't get me wrong, there's some outstanding coaches everyone knows about, but then there's the next level and that's most of them who are just competent at their job and so and so likes working with them.
Considering all of that, he wasn't picked up by an NFL team so where does he go. Somewhere he knows and has worked with the guy making the decisions. The rest is history.