My experience may differ from more recent students. I would 100% encourage him to go see what it is like and see if it is something he wants to give significant time to. This is going to sound very negative, but I am actually a big fan...
1) D&B has LOS - limited on-season status. This takes the place of your athletic extra activities (intercollegiate or intramurals)
2) You practice daily
3) You travel to football games (including bowl) and basketball end of year tournaments
-understand it is a contractual obligation (you should read the language -- you can rent a band or cheerleaders, but you will have one)
-understand that this comes at a cost of 4* time at home at Christmas and/or Spring Break
4) You play at football games (home and away) and a subset of the band will play (think on rotation) for Men's and Women's basketball home games
5) You are not prevented from joining other clubs, but your time will be very limited.
6) D&B does not march woodwinds - yet some former woodwind players try to learn new horns
I came from the top high school band program in the US, and I served as an ALO to that school after separating from the Air Force. The drumline recently won PASIC as the top drum line in the country. I am about the biggest band supporter you can think of - HS Drum Major, etc. I was great friends with the former Director when I worked at USAFA and considered applying for the role because I knew he was retiring. With that said, I am not big on Service Academy bands. There are too many challenges before them to be at the same level of today's top HS programs. Most SA students are high performing, competitive, and achievement oriented - but oddly, that does not translate to D&B.
I tell all my band student candidates that SA marching band will be a step down for anyone from a top high school program. Know it going in, and don't be surprised by it. You've been warned. Key constraints:
1) SA do not recruit musicians
2) SA do not have music majors like the big universities to draw top talent
3) Funding limits you to flying on a cargo plane and sleeping on an elementary school gym floor in many cases (but hey, at least you got to go...)
4) Too many other items competing for SA student time. Most leave after 4* year.
I went from a HS program where every student had a tuner. Every student took private lessons. Musicianship was off the charts. When I arrived at USAFA, I was SO jacked for tryouts and was PUMPED! The audition day came, and I tried out for the bass line in an empty classroom in Fairchild Hall. That night, a senior stopped by my room and told me I had made it, and I was a 4* on cloud 9. I WAS GOING TO BE IN A COLLEGE MARCHING BAND!!
Then, I went to the first practice. The Drum Major was a walk-on cymbal player with no prior music experience. There was one tuner for the band. Guys and Girls who had spent their entire musical career up until this point as a string or woodwind player were learning to play horns like it was beginner band all over again. I went from thinking it was AWESOME that I was selected for the group.... to wondering WHO DIDN'T GET SELECTED???? For this being a military school, the marching was horrific and you would think this group OUT OF EVERYONE would have been amazing because they had likely spent the 4 yrs of High School marching long before they stepped on the grounds of USAFA.
Everyone's background is different. Everyone's reason for joining D&B is different. I had a personal issue reconciling the differences between the program I had come from and the program I was now in. For a number of reasons, I did not stay in D&B after my 4* year and went on to pursue other activities that I had never been able to do before and in the end, I wouldn't change it.
I still think there is A LOT of fun to be had during football season. For most 4*, the comfort of being in a safe space doing something that is very familiar to you, in a world of unfamiliar, is very helpful to the emotional well being of that first year.