I think it's an all too common fallacy to assume that being exceptionally experienced and skilled at something makes you the god of that thing, and your word becomes dogma. He is the guy to talk to about breaking down fish, but not about sharpening--al least not without finding out if he actually has any sharpening credentials. He's a butcher, not an engineer, after all, and people in trade jobs(even the top of trade jobs) often have a "whatever works" approach, and don't need to alter or experiment with a formula that is clearly working for them!
There are people in Japan and Seattle who don't waste an ounce of fish, and can dispatch tons of fish with effortless finesse--all while using cases of disposable knives. Breaking down fish like a pro is not about knife skills--it's about fish anatomy. If you have a good understanding of what an animal looks like inside and out, you can break it down with anything--my father slaughtered and butchered every animal we raised or shot growing up with a 4" Buck knife, and it never got sharpened.