Howdy, class of '26 former cadet here.
Definitely go all-male. I was in a co-ed unit, wish I would've gone all-male looking back.
Navy/Marine Corps:
K-2: incredibly fit, best Navy-Marine Corps outfit in my opinion, maybe even best outfit in the Corps right now.
C-2: Great outfit, all-male, strong culture. Good alumni, solid dudes in there.
P-2: Not necessarily all-male per-say, but they've kept a decent culture after H-1 got disbanded and their cadets moved there. They have very few females, but the ones I know in P-2 are awesome and won't hinder your son's Corps experience.
E-1 Jocks: Athletes, strong culture, best Army all-male in my opinion especially if your son loves sports. If he's not an athlete though, wouldn't recommend.
D-2 Dogs: Decent amount of studs, they got some weirdos in there right now to be honest though.
B-2 Patriots (Boozers): I love the boozers, some great dudes in there. Definitely about as old army as you can get nowadays.
L-1 (Lone Star Company): Country boys, good ol boys, super dirty hallways/bathrooms from what I remember (most of the all-males are though hahaha). Awesome people though, they used to basically run the Cavalry unitz
Sq. 17: Basically a men's org nowadays. Also very athletic. Summer camp counselor vibe from their cadets. Definitely the most social with outside orgs and sororities if your son is into that.
At the end of the day, I don't think you can go wrong with the all-male units. Hopefully that helps.
I'm also a Navy contract, I leave for Pensacola in March so please let me know if I can help you with anything.