Well, I may be completely off base here, but I'm not sure a tour of living quarters or shadowing someone, is a realistic option. And as a wife of an Enlisted Master Sergeant, I must say that I am just a tiny bit offended by "especially if they are not joining as an officer" :). My husband is doing what he loves, and has been in the same MOS (field) for over 18 years.
To the op- I would find out what he wants to do in the service, and then help him decide which route would be best for doing that job.
My oldest ds recently decided he wants to join the military and has decided to go the officer route because he's already in college. I have shed a few tears (in private) over this, but I will support his decision 100%. I asked him if he had prayed about it, and he said yes. My job now is to support him and pray, pray, pray.