Without football revenue. His most important job is to ensure the football program is excellent. He should know what world-class programs look like - recruiting, strength and conditioning, player development, academic support, nutrition, assistant & staff development, analytics, alumni and fan engagement, etc and ensure our program meets those standards.
The coaches job is to make final call on recruits, game planning, hire/fire his assistants and win games.
Hiring/firing coaches, taking care of donors and ensuring each athletic program is meeting standards including taking care of its athletes and fans is second, third, etc in priority.
He knows from personal experience what a sub-standard D1 coach/program looks/acts like. If BYU ever needs to fire a football head coach it probably needs to fire the AD who made the recommendation for the BOT hire.