I don't know if you'll find a military school that will take him with his record and history of MH problems.
The substance abuse is going to be a big issue. He is going to have to go through detox and withdrawal if addicted (NOTE: alcohol and benzo withdrawal can be fatal and should only be attempted under close, inpatient supervision).
It might be better for him to go through rehab and get some clean time under his belt before sending him off to military school.
An Residential Treatment Center (RTC) or emotional growth boarding school might be a much better route.
Due to his issues, he is likely not suited for a military career track anyways.
