I would def. do AP Chem.
The fact is they will look at the rigor of their course load and the school profile too. If he takes the most rigorous course load available it will help him. I would probably take APUSH with it, because it is one of the easier AP classes.
That being stated remember not to get tunnel vision. It is great to have the AFA as a goal, but keep your mind open to all options, so also look at what is good for their plan B.
2 yrs ago none of these cadets as a rising junior knew that their class size would be reduced by @20%. You don't know the future, and so much more goes into the equation than just academics.
You can be valedictorian, but no EC's and you will not be sitting pretty.
It is a WHOLE student approach. That means taking a rigorous course load and having ECs. Too many times on this forum do we read, I never played a sport, and they are rising srs. That hurts them.
Academics is 60%, you can score 100% on that, but only 20% on the remaining 40. In the end, that would make you non-competitive.
Also, the one thing candidates and parents forget is that medical is an issue. The DoDMERB forum doesn't exist for any other reason than it is highly needed. Make sure, that you are prepared for them to go through a rigorous medical eval. This is not a sports or yrly physical where you are out in 30 minutes. This is their entire medical history, and everything from their ears to their toes are checked.
Let's be honest you need a waiver for braces (always granted, but still a waiver).
As a realtor I always say don't be too busy jumping over the nickels to pick up the pennies. In other words everything matters.