People do make money from streaming on Twitch--the same way people make money off YouTube: the vast majority of people don't make it big. And it often takes a stroke of luck before you get there (such as being featured by Twitch, having your stream plugged by a famous streamer, etc.).
My understanding its very, very hard work. It's not just sitting back and playing video games with recording software going. Most of the big streamers stick to a very strict schedule and stream 6+ hours per day M-F and 10+ on Sat/Sun. They often get stuck playing whatever game that got them "famous" and rarely get the chance to play new titles except on their own time. You have to have a well designed Twitch page as well as professional screen overlays for the broadcasting software you use--this means having or hiring good graphic design skills. Most big streamers have "chatbots" active in the chat that do various things and various "plugins" that make stuff happen on the screen, for example, if somebody subscribes, follows, or donates. I have no idea how these things happen, but I assume they mean either some sort of programing skill or paying for the plugin/chatbots. You have to cultivate a brand and stick with it--and self market, self market, self market.
My intent isn't to be discouraging--just realistic. It is very possible to make a good living on Twitch, but like any career, it requires very hard work, a stroke of luck, or both. If he's serious about it and understands the work involved, it might be worthwhile to try to find a mentor of sorts to show him the ropes. Also there are books out there on "how to be a successful streamer." Don't waste your money on them.
If he's not interested in college (it's not for everybody), would trade school be an option?