Not the PLA either... 
Made a new account to hopefully minimize self-doxing, but here's some background. I haven't lived with him in 10 years and I left the country 4 years ago. We don't really talk all that often, but he had messaged me with some questions about photography and then brought it up.
I said something like "I'm sure you're aware I don't have a very fond opinion of the military". He said "I'm not too enthused with the idea either, but I need the security and discipline that it will provide while I try to find something to dedicate myself to and I've been in this dead end job for about 2 years and my soul is decaying".
I told him he can come live with me, that it's easy to get a 1 year visa and I'd happily pay for flights and I have a spare room. He said he'd think about it but "needs physical activity and more friends and connection in general". I tried to explain that I go climbing multiple days a week, volunteer for search and rescue, and play board games with friends every week that he'd be able to hang out with.
I get the impression though that he thinks visiting would just be putting his problems on hold for a year; maybe he's right about that, but I think living somewhere other than our shit hometown would give him a lot of perspective on the world and help him maybe realize that what he actually needs is a community of some kind. I don't want him to make a huge fucking mistake because he feels hopeless and gets pressured into it by our conservative step dad or some recruiter or whatever.
I also briefly tried explaining some issues with the US military, but it's a bit hard to undo decades of american "education" in one conversation. He said "my moral code is also not nearly as strong as yours, and I have very little strong feelings toward very much at all outside of just trying to be a good person". I assume he reached out to me because he's having some doubts.
Anyway I tried to make it super clear that if he wanted to come live with me or if he wanted to do a work visa somewhere else I'd pay flights and anything else and help in any way I can; I'm not rich, but I have a small emergency savings.
I think I've heard there are organizations of leftist / anti-imperialist veterans? Maybe one of them has information I could send him. Any advice or ideas would be appreciated.
I think that your approach was very intelligent and constructive and he should take your offer, though it sounds like he likely won't.
I think this is only useful if he has a specific type of personality, but have you considered asking him what being a good person even means if it's divorced from morality? That's what being a good person is unless he's on some "master morality" shit where being a good person means being powerful and hot and wealthy, which I don't think is actually what he's thinking of. It sounds to me like he literally just hasn't considered the concept of morality very much and doesn't understand that being a good person doesn't just mean being liked by the people around you.
Have you asked him about becoming a fire fighter or something? Lots of discipline and physical activity and a need for a close relationship with coworkers while being beloved by the local community rather than being hated by it for literally fucking murdering them. He said himself that being in the military requires devotion, and does he really want to seriously devote himself to a cause that he himself cannot defend as being good?
It's probably also worth pointing out that lots of vets get fucked up and then mostly abandoned by the state, with veteran homelessness being a huge problem, along with addiction and suicide because they are left in poverty and misery. If he's really interested in long-term thinking and doesn't believe he's going to quickly become an officer, joining the military is a bad idea even if he doesn't get killed or physically disabled.