He has developed a following because of his repair videos. He is an advocate for repairing your own stuff, has put out hundreds of videos teaching people board repair and has even put out an extensive guide for beginners: https://docs.google.com/presentation/d/1PkeO_lC5WTPScSV3ZzEE...
And he is internationally renowned for Macbook board repair and literally receives and fixes laptops from all over the world. He actively tells people to not watch his videos on YouTube and prefers Vimeo. I have no proof but I'd bet that his revenue from his YT channel is a small fraction of his overall income from his repair business and online e-store.