One way to start making a game with no programming knowledge is to use one of the many game engines specifically tailored for a genre of game. And since they're designed with a single game genre in mind they usually don't even require you to learn a scripting language. To name a few:
- RPG Maker - for 2D role playing games (I loved playing around with this when I was his age!)
- Visionaire Studio - for point'n'click graphic adventures
- M.U.G.E.N - for 2D fighting games
And although he might need to learn a bit of programming it shouldn't be that hard to use:
- Flixel - A Flash game library, general purpose but with a lot of facilities to help make platformer games.
- GameMaker - is also famous although I have never used it.
Also, since he's getting started, I do recommend starting with 2D games before moving on to 3D games.
I think RPG Maker would be a great place to start because while you don't need to write code directly, the way the event system is set up makes you need to think logically which is a must for a programmer.
You basically create events, set up the conditions for them being triggered, and add a series of actions with configurable parameters. You also have flags to set which would be the equivalent of variables, and you can control the flow of these events using conditionals and loops. All in all this sort of thinking will translate very well to real programming later on.
Visionaire Studio is also very similar to this but for another genre!