MEPs does NOT test for steroids. So from the time he hits MEPs till his ship date, he'll need to get off 100% and be back to being natural. Even though it's the army, there is some PT I assume, in between eating ice cream and walking around with their hands in their pockets, nasty.
Once he gets out of bootcamp, MOS school, hits his duty station, he can think about getting back on gear. Plenty of guys use gear in the military. Especially now since it's damn near peace time, and deployments are few and far between; depending on MOS.