Maybe his intentions are okay, but you can find numerous files for all of those games for free elsewhere. There a lot of high quality files out there, and if you own a PC version of, say, NHL 06, there's absolutely no point in considering with sites like rosters.arenacenter.net that update daily.
For consoles, though? Hmm...Check his prices. I'd be concerned about speed and reliability, but if it's cheaper than buying a cheat device for $20 I'd consider it.
With NHL 06, though, if you get online with your PS2 or XBox the roster update is as late as March 9th as well.
In regards to his legitimacy, I doubt everything he's done is original. chances are that he's trying to pass someone else's work as his own, but who knows? If you're that curious about all of this, contact the guy.