How much does your son want to do programming? Does he do it for fun already? What other interests does he have? Are there parts within these interests that co

How much does your son want to do programming? Does he do it for fun already? What other interests does he have? Are there parts within these interests that could have relevance for programming? For example he might like bird watching, so perhaps a mobile app for birding might be good, or he might love platformer video games, etc etc. In short, he should do what he is interested in, don't worry about the choice of technology - by far the most important thing is that there is some interest, passion and enthusiasm. The choice of technology is less important than the choice of what to do.