Our narcissitc coach has apologized and "appears" to have changed. How long before he blows his fake cover?

Seriously, I've researched the definition and our coach is a true narcissist. He's treated the kids terribly AND the parents but when confronted he has gone above and beyond the call of duty to apologize. He's told us each how Wonderful our son is and what a great player they are, etc. The sad thing is, we each got a similar "description" of our son. He ACTS as if he had no idea how he was treating them before. My question is, how long before this facade ends? How long before the narcissistic behavior returns or does he have the potential to now really blow because he feels we're controlling him?