I think the hard part is the initial phase, before you know how to make things move, how to draw to the screen, how to handle multiple states of multiple object

I think the hard part is the initial phase, before you know how to make things move, how to draw to the screen, how to handle multiple states of multiple objects without the code getting incredibly messy and unmaintainable etc. If I had to guess I'd say your brother spent a lot of time building many little things before getting to a point where he can quickly build a basic prototype of any game he saw.