It all depends on what you want him to learn :)

Codecademy seems fine, I've also found https://codecombat.com/play :) maybe it's more fun :)

If you want your dad to be full-stack dev :) Maybe push him towards learning backend development ( like python as you mentioned ) and use some MADPs ( Mobile Apps Development Platforms ), like https://www.kinetise.com. Which basically allows you drag and drop mobile application and connect it to your backend. It will give him more fun to create mobile apps as well.