This is how my son was able to get to a D1 school for men's volleyball. Got a massive academic schollies from the school and was a PWO for the team.Any one receiving athletics based aid for any sport in any amount that plays football automatically becomes a headcounter for football. This is the way.
Walk-On's are allowed to have grants and other academic based aid if it is granted through the normal university application process or by outside, independent organizations (the corn used to use community scholarships to get the big farm kids in as walk-ons, but I think the NCAA tightened the rules around that). I am unaware of any full academic scholarships that CU grants. If an instate kid was a Boettcher scholar, and wished to walk-on for football they could. As an employee, Coach Mathis could also designate his tuition assistance benefit to Caleb and of course because he is a dependent of an employee he gets in-state tuition.
Worked his ass off for 3 years that coach granted him an eighth of an athletic scholarship which made his senior year paid for.