My son (16) made a Roblox game with his friends. I think it's pretty neat and I thought I would share. It comes out this Saturday. They have been working on it for a year.
Here is the Youtube trailer - https://www.youtube.com/watch?v=u6uKpbv4YlA
Looking at how many people worked on that game I think your son is running a full on game studio. He will learn a lot of valuable skills and have a great time doing it.