he's not signing an LOI but a financial aid agreement with the school. You can do that after Aug 1. Not sure how binding it is though. I think in the SEC anyway, a financial aid agreement carries the same weight as the LOI.
Basically, they only bind the school to the scholarship offer. This doesn't bind the recruit, but it does make it slightly more official than a verbal commitment.
Apparently though if a kid signs this their recruitment is treated as if they signed a LOI. So they're allowed unlimited communication and the coaches can publicized their commitment. If that's true, then that's a pretty big deal.