To be fair to mcotter he is referring to GameBlender, which makes it possible to create interactive games using Blender models and animations using Python scripting and logic bricks.
"Game Blender is used by inserting "logic bricks," "controllers" and "actuators" to control the movement and display of objects in the engine. Game Blender is also able to be extended via the Python programming language. Game Blender is bundled with Blender 3D which can be downloaded freely from Blender's official website, http://www.blender.org/."
http://en.wikipedia.org/wiki/Gameblender
He's not interested in coding the game engine, he's simply interested in learning how to use Python and logic bricks inside GameBlender. This is akin to modding or using a pre-built engine, so I really don't think it's useful to keep telling him how hard it is to code an engine from scratch.
With that said, I don't really know how much use we will be. The experienced people on these forums tend towards writing the actual engine themselves, relying upon more 'universal' mathematical conceps. Using another program requires somebody with experience specific to that application (GameBlender in this instance), and I personally haven't created anything with GameBlender.
The only reason I even have Blender is to have a wider range of file formats that I can fiddle with (e.g. to export and import, such that I can convert models to my own .ntmdl format).