Well, the Army Reserve might be good for him---it might give him some discipline and structure that he can build on as he goes along. And since he isn't active duty, he avoids most of the major combat deployments and such, unless his unit is activated; but lately the Army has been using state National Guard units for that sort of thing.
And as for the prison, it all depends on the systems they have in place to safeguard both the inmates and the staff. Some facilities, especially the ones run by private corporations instead of state governments, tend to be a little more lax in their procedures; but in this day and age, the chances of prison staff getting hurt in a prison is quite small---the safety regulations they have in place are designed to overlap and make sure that everybody is protected. Don't be influenced by stuff you see on TV, where the inmates attack a prison officer and raise havoc; that sort of stuff really just doesn't happen any more.
If you have other questions or concerns, don't hesitate to ask me---I'll help if I can.
