To just get a feel for coding in general I would recommend Scratch - the visual nature will help make sense of what's going on
@kitten_tech https://scrimba.com has a decent free tier for a few languages. Not tried them myself, but Iβve heard good things about them!
That really depends on what this person wants to "code".
I was lucky to start my teenage years with an Atari 800 and Atari BASIC (rev C).
There's a really good emulator that I run on Linux (atari800) which is reasonably easy to set up. That would give easy reach to a lot of the basics: graphics, sound, and a bunch of BASIC programs that can be examined to see how they work.
@kitten_tech I like Automate the Boring Stuff:
https://automatetheboringstuff.com/2e/chapter0/
I've recommended it to folks in the past and people have generally enjoyed it.