A HC needs to come out quick and forceful in demonstrating that the Offensive production was unacceptable even if it was run by TFD. The bar has to be set high at BYU and people need to know that.
Plus, how are you going to trot Ty out there on the recruiting trail while behind his back your are interviewing for a new OC? That is some shady business practice that wouldn't go over well with anyone.