I'm guessing that his primary fandom has moved to BYU - but that he still has a soft spot for Utah and wants them to do well when BYU isn't playing them.
Honestly - having more legacy kids from one school attend the other - going both ways - may be one of the best ways to dilute some of the poison in the rivalry. I'm good with there being rivals - I'd just like it to be a little more fun and a little less toxic.