I know pretty much nothing about writing code, programming, etc.

DS8 is interested in making mods (?!? Don't really get what that means except it sounds like a modification to an existing video game) and inventing new games.

Are there online classes for this? What kind of computer would he need?

Youth Digital has an intro to modding class that our household enjoyed.

Coding is only a small part of game development. Most important is that he studies many many games: Poker, Backgammon, sports, . . . those are all very important.

He can create games very fast using only paper, pen, and perhaps scissors. This is the fastest way to iterate—especially if he designs alone. Dice and coins can be used for randomization and probability. The core of any game are its rules. He can then use various tools to create the code and content of the game on the computer.

For modding (your interpretation is correct), many modern video games offer free modding tools with documentation that he can use. These games also tend to have active, and (hopefully) helpful modding communities on various internet forums.

A very good friend of mine is a quite legendary video game director: Tomonobu Itagaki. I learn quite a lot from him. He has a personal Facebook profile, and a company profile. If your son wishes to hear some tips directly from a professional (and genius, I can ascertain), he should introduce himself and ask some questions.

Thanks for the suggestions. I purchased Youth Digital mod design 1.

I talked to his school about it and they're going to let him bring it there and work on it as part of his curriculum. He is super excited and is planning to take app design 1 next.

That's great!

User interface design is also a very important part of video game development. I have found Microsoft's UI design guide to be the best. Apple has interface guidelines for iOS that he may be able to generalize principles from.

I don't know how approachable these are for him at his current level, admittedly. If not yet right now, they will become valuable resources later on.

Anything here helpful....

http://www.scouting.org/scoutsource/boyscouts/advancementandawards/meritbadges/mb-gdsn.aspx

Update here - he is REALLY enjoying the Youth Digital class. He's worked it out with his teachers that he spends 20-30 minutes of class time on it everyday. He would spend all day on it if he could but this seems like a workable compromise.

It is nice that his teacher left a career in programming to be a teacher.

Youth Digital has had several holiday sales if anyone is interested.

What do you think of https://www.scriptacademy.net ?