My gut says he buys the NA beer to explain the beer breathe but has a stash of the real stuff...or buys the real stuff while out too and pounds it before he comes home.
If that's not the case he's setting himself up for a relapse and isn't taking his recovery seriously. My RXAB always wants to sit at the bar at restaurants to eat...he does this alone, with other people from AA. That's like me thinking I can talk to my X on the phone and not get upset. Why test yourself when it isn't necessary?