Just so that we're clear, I doubt he is earning anything near that at the moment. That article was written when people were paid according to the number of claps they received. Everyone was gaming the system, and it was removed about 18 months ago.

People had agreements that they would all clap 50 times for other people if people clapped 50 times for them.

When Medium shut that down and paid according to reads, many people left because the bottom line is that nobody read them. They were paid for claps, and their earnings dropped immediately.