I'm 67 and love programming - all self taught. Without knowing your father let me suggest this with a caveat; there is no right way to learn something as we are each different. What works for one fails for another. Here are my suggestions. First, Python. A "class" or online course doesn't really allow for setting a personal learning pace. I found "Python Programming: An Introduction to Computer Science" by Zeile to be perfect for me. Second find something - a goal - to motivate the process; a website for a local charity, a payment site for a small municipal water company or for the local town office or volunteer fire company etc. Build it out with Django. And along the way build out a personal website with Pelican. Turn a Chromebook into a linux machine with GalliumOS and use only text editors - IDE's just add unneeded complexity. If you have a compelling reason to learn something - you will. When he builds something - put it on Github. It becomes his resume - along with his dialog of "the road to learning" he might post on his Pelican blog! Results trump certificates and degrees.

Your comment is quite assuring comforting. I guess I'll just try to push him on to lear new things until he's found something he likes :)

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.

Well I kinda want him to figure that out himself. I've been thinking of giving him a quick hands on overview of some tools, algorithms and design patterns. Maybe even give him some sort of hobby project to work with.