I would sit him down with a cup of coffee and say the following:
"Al, Im not sure if you are aware of this, but you have the greatest football coaching job in the history of the sport. And guess what? You are failing at it because of your own ignorance. If you don't completely change the way you manage the game day aspect of your job, I guarantee you that seven years from now, when you're a D coordinator at a mid major university, you WILL look back with regret over how you ****ed up the best job you will have ever had in your life.
You were completely stubborn until the heat got so bad that you finally changed your defense for four games. Interestingly, in your 8 year head coaching career, you've had two signature wins (Against Cincinnati and Duke, both in 2014) and interestingly, both of those wins came when you played a completely different, more aggressive defensive then you normally do. Is that not enough for you to realize that you need to change, NOW?!? If it doesnt, then be prepared for you to ultimately be fired for failing at the best job you'll ever have. Its on you at this point, no one else."