Hey there, Alice,
I went to an all boys military boarding school from 7th - 12th grades. I was not a bad kid - - it was a family tradition thing. I basically had a good time there, still keep up with some of my classmates, and have considered sending my sons there if we’re out of local options and also win the lottery (more later).
As you can tell from some of the posts here, the philosophy of the school is very important. Some military schools (and regular boarding schools) are set up for problem kids as a treatment for “juvenile delinquency.” Others, like the one I attended, do not allow JD kids at all. At my old school, students would have to earn an invitation to return for the next year, and kids who were continual troublemakers didn’t get asked back. So… research the school and see what their policy is with JD kids, see what their college placement rate is and see which colleges the kids go on to. That should go a long way into weeding out less desirable ones. And ix-nay on the co-ed ones. It’s just a bad idea for that age.
As for structure, the days at military school are, as others have said, very regimented. Twenty five years later you can give me a time and I can tell you with pretty good accuracy what I was doing at then. (For right now, I was in fourth period class before lunch.) A boy at such a school can be expected to be told when to get up; will march to breakfast, have classes, march to lunch, have afternoon classes, have afternoon activities, march to supper, have some free time, have about 2 hours of guided or independent study hall, have some free time, and then have lights out. Our days started at 5:45 am if you wanted a morning shower and ended at 9:45 pm.
Depending on the school and his activities, he can expect rationed free time. At my old school, non-varsity athletes got free time on Wednesday afternoon (varsity guys had practice). Everyone got free time Friday night, Saturday after lunch, Saturday night, and Sunday afternoon after the formal review formation. Boys with higher rank (more later) earned dinner permits that allowed them to skip the meal at school and go into town to eat (paid for with their own savings).
Along with structure, he’ll get demerits or tours or gigs or some other form of stratified consequences for not following rules. Being late isn’t tolerated. Messy rooms are out of the question. Not doing homework. Cursing (if caught). Disobeying. Unshined shoes, unshined brass. Systems vary, but at my old school low level infractions earned a boy 1 tour, mid level infractions were 5 tours, high level ones were 10 tours, and disobeying or other serious offenses warranted “x” tours - - which was between 30 and 50. Boys with tours had to attend study hall for a set period of time for each tour instead of getting free time on Weds, Friday evening, and Saturday afternoon. Some boys would be selected for work details (light duty - - raking, sweeping, etc.) on Saturday. Everyone got free time on Saturday nights and Sunday afternoon.
Boys who were good students and good at following the rules were rewarded with rank. Everyone started as a recruit and worked their way up. The highest you could get your freshman year was private first class. Top sophomores topped out at buck sergeant at the end of the that year. Juniors could get up into the sergeant first class territory, and seniors in key leadership positions (company commanders - - analagous to dorm proctors - - and platoon leaders - - analagous to floor proctors) would be lieutenants and captains.
With rank came extra privileges, but also leadership responsibilities. Leaders were expected to enforce rules when faculty were not around and were expected to set a good example at all times.
Schools vary, but you should be looking for a good mix of academic, athletic (varsity and non-varsity sports), and extracurricular activities. Good schools should have solid academics, sports for all levels of ability/interest, and plenty of other things to do such as drama club, flying lessons, outings club, computers, etc., etc.
As for expense, you can expect to pay a lot. The school I attended lists on its web page that tuition and fees are $28,000 per year. There are scholarships at that school and financial aid, but there are no full-ride awards that I know of. If you’re interested in the school I attended, please send me a pm or email.
My $.02-worth - - the kid is 9 and is probably going through a phase.