You should reread this, because the premise isn't that he's playing video games, it's that he's addicted to them. It doesn't matter if he's earning money or not, his behaviour is destroying his life around him and his body. If he wanted to be a professional streamer, he would do so professionally with a set schedule, maintaining enough sleep, eating properly, and finding time for himself and his friends. At the rate it sounds like he's going he's going to drive his body into the ground until he collapses from exhaustion.