I'm a Lone Peak guy, my son has played with Chase's little brother Dakota for a few years, so I hear a lot of conversation, but am far from a family insider.
Totally my opinion, but based on what I hear...the Taysom Hill situation has changed the dynamic for Chase. 4 years ago Utah was seen as the local school with the best opportunity for a read option/spread/passing QB. That has changed. The more press Taysom gets, the better the chance Chase ends up at BYU.
With all of that said, their family is high integrity and I think what has been said about Kyle is true. If he is still coaching, and promises Chase a real shot at QB, he stays because of his earlier commitment.