I then set up my old Mac with Love 2D and Atom, but he wasn’t interested, because he’d also have to learn about files, directories and the command line.
He spends a lot of time on the iPad, so I recently bought Codea. With a bit of help, he was able to write code to draw some shapes and became very excited about it. I evaluated it myself and was able to make Pong in a few hours. It has loads of examples and can actually be (and has been) used to make quite sophisticated iOS games, right on an iPad. It helps to have a Bluetooth keyboard so the on-screen keyboard doesn’t occupy half the screen.