I'm not so sure. It would have to use iAd on iOS to do display ads, and Apple would yank that access with a breach of the terms of service. I doubt he's still getting "tens of thousands" of dollars from ad revenue in Android alone.
(It was probably because I was always ditching and dying that I saw them; I was pretty hopeless at it, although when I plugged my Xperia S into HDMI, the phone ran noticeably slower so it was significantly easier to play.... just a tip for anyone out there....)