He's just saying "non-game apps"Since term "applications" is quite broad in my dictionary, I would ask for some more details or topics I should take a look at.
Indie games just aren't that profitable. He might be better off making applications if he wants money.
I'd still like to expand on this, though...
Applications are pretty much programs which help you somehow or make life easier, that aren't games. Like, there is a market out there for art programs, but you have to do something Photoshop, GIMP and Paint.Net currently don't, or do it better than them. If you want a smaller, more niche market, you can focus on making game development tools for sale, but that market might require a little more work, and might possibly have less pay.
Here are some examples:
Game development applications