I am sure he does. Like any parent a ton of questions comes to my mind, that I would want to know the answer too.
1. How much of a good academic/social fit is the current school?
2. How connected is he to his batallion already?
3. Will the spring semester give him some breathing room from football?
4. Would he be losing anything in his acadmecs/career by "the D3 school" he is considering? Or would he gain something?
5. Would he be giving up anything academically or career wise in the military to pursue football?
I don't need the answers, but he should be able to answer these. He definitely needs to talk to his cadre. And I get the sports thing, it is hard to let it go, but he will be letting it go soon enough whether it is now or in 3 more years. I realize he is probably not playing much being a walk on, and the lure of going D3 and playing is probably part of it. I have two playing D1 sports next year, and that is their single focus besides the education, and they are both worried it will be too hard, so I cannot imagine how distracting this is for him adding in ROTC too. The difference for them will be their sport is paying for their education, where ROTC is paying for his. I guess my bottom line is, what is best for his education and his career should come first, and then decide if football works in, without it paying for his education it would be hard for me to advocate for giving up anything else in the education, career or even social aspect of a college choice. Just my two cents, and none of my business, but thinking you probably wanted our opinions since you asked! We struggle with our oldest (MS1) not being able to say no to opportunities and wanting to do it all, so I do get how difficult this is, good luck to you both!
*edit- also remember ROTC will get more demanding as the years go on. I do know there are cadets/athletes who have made it work, so not trying negative, just saying there is a opportunity cost to every decision and this is a big one. Good luck.