He spars at the gym, and watches a ton of tape. He was sparring with open class fighters with 40 + fights when he started, sparring with pros, and getting a lot of time in. His drive came from people telling him he couldn't do it. He is a good fighter, and regularly goes to nationals.
Completely self trained? None of us are completely self trained, learn a lot in sparring. We give each other feedback. But at the gym the trainers don't shadow over you. They may watch you spar, give feedback, and corner you. However, they rarely take you from scratch, they don't even too much watch out for you until you prove you have potential.
Our gym was number two at the tournament this year behind Tony Harrison's gym. They put out solid guys. May not work for everyone, more the exception I guess.