If his average is that high then he's been bowling enough to know the rules about outside interference in knocking pins over (pinsetter, ball jumping out of the gutter, shooting a pin with a pellet gun (lol), etc.). But then again, the way you describe him, he's just a giant [censored] who probably thinks he can do whatever he wants because he's the highest average in the league.
In my Tuesday league there have been a couple of cases where a pinsetter knocked over a pin or a ball jumped out of the gutter, but its non-sanctioned and everyone knew what the rule about it was, so it was let go. If that happened in my sanctioned Wednesday league, you can bet I'd be letting the guy know that his score was false and that he was cheating.
P.S. No one actually shot a pin with a pellet gun, its just funny to think about.
15.5lb MoRich Nsane LevRG (medium and medium-heavy)
15lb Roto-Grip Cell (heavy oil)
16lb Colombia White Dot (spares and extreme dry)
16lb Roto-Grip Neptune (light and dry)
High game: 300
High series: 779