Coaches can't make kids focus, work hard and so on and so fourth. Baseball is a grind, especially when you have class. Not everyone of those guys is capable of showing up to the park every day with 100% focus, ready to compete their tails off.
I'm not saying he should not be fired or that he should have been the guy hired, but at this point I don't think it was a bad hire. He took over a complete dumpster fire at NSU fwiw.