For the Python route -- or Javascript -- there are a huge number of introductions and learning projects, some of which will appeal to a teenager. For MS Excel,

For the Python route -- or Javascript -- there are a huge number of introductions and learning projects, some of which will appeal to a teenager. For MS Excel, I've never seen any training or learning materials that are interesting even to already-employed office workers. Maybe there is a local small business that would be willing to have him help with their finances? A value of MS Excel as an introduction to programming is the ability to create macro scripts by recording what you're doing. This can help establish a mental model of scripting as writing out what gets done.