I've seen some of this footage on a commercial recently and remembered that I was lucky enough to see the whole story behind it.
Trust me, those drills are hard to keep up with at the college level. Dad is doing a pretty good job of keeping up considering his pushing his son along as well.
Plus, the son is at a bit of a disadvantage because he can't see what's coming up in front of him. Things happen on the field ... some of the older fields still have bumps and stuff in them. When you're marching you can see that and allow for the abrupt change and stop playing if necessary. This player is subject to more than his share of clams!!
Fantastic story. If you're interested in this kind of stuff, you should read Musicophilla by Oliver Sacks. It's about Music and the Brain, and he discusses at length why many blind people end up excellent musicians (beyond the obvious emphasis on hearing due to lack of vision).