I'd use Wrath of Ashardalon to introduce him to D&D. Then go to D&D Essentials. 
Exactly what system do you use yourself?
When I look at introducing new players to D&D, there are two factors that are uppermost in my mind:
* What system am I using myself?
* Who will they be playing with?
If the answer to the second question is "me", then the answer to the first question is the system I'll probably introduce them to. Yes, I might strip it down a little (essentials does that nicely for 4e), but using the system I use will allow them to get into my games easier.
If the answer to the second question is "their friends", then you need to pay more attention to what game their friends are likely to play: and that's often going to be one that is readily available. It's all very well to suggest an Out-of-Print game, but if you're the only person who has copies of that game (or can get them), then it's a roadblock in terms of getting other people to play with the new player.
Five is young, very young. At this point, things like "too complex" apply to even the simpler games: much hand-holding is required.
Really, the question is much more at this stage: what game do you want to play with him?
Cheers!

Exactly what system do you use yourself?
When I look at introducing new players to D&D, there are two factors that are uppermost in my mind:
* What system am I using myself?
* Who will they be playing with?
If the answer to the second question is "me", then the answer to the first question is the system I'll probably introduce them to. Yes, I might strip it down a little (essentials does that nicely for 4e), but using the system I use will allow them to get into my games easier.
If the answer to the second question is "their friends", then you need to pay more attention to what game their friends are likely to play: and that's often going to be one that is readily available. It's all very well to suggest an Out-of-Print game, but if you're the only person who has copies of that game (or can get them), then it's a roadblock in terms of getting other people to play with the new player.
Five is young, very young. At this point, things like "too complex" apply to even the simpler games: much hand-holding is required.
Really, the question is much more at this stage: what game do you want to play with him?
Cheers!