Does he want two separate things to play at once, or does he need both analog audio as well as digital audio so you can feed the zone2/3 of the Denon receivers? If you just need analog audio, then I believe that the PS3 now supports multiple audio outputs concurently. This feature is enabled in the sound settings. I have a PS3 and I have NOT tried this, but it is a newer feature that was definitely not there a couple of years ago. You just use the old PS3 proprietary analog cables it came with an you hook up the red/white cables along wtih digital audio and turn on the multi-format audio output connection type. Since I have a PS3 and want/need the same thing, and I did a bit of research on it, it looks like it will work.
Otherwise, from a iPhone/iPad, AppleTV with AirPlay is a pretty good completely wireless option.
AppleTV will also stream from any iTunes enabled PC.
If he isn't an iPhone type of person, then he may prefer one of the 5,000 other media players which are out there. None of them under $100 are excellent, but they all do a reasonable job. A hard wired network between the two locations is a real benefit to this setup.