Bitter, dark, and yeasty, eh? Definitely have him try Schneider-Weisse Aventinus. It's a widely-available German import so it should be fairly easy to find.

I don't know anybody who dislikes this beer. (I suppose it's only fair to note that I immediately cut off all ties with people who don't like this beer.
I can explain it to you but I can't understand it for you.