If the guy only has the statistics to show to the unbeliever, then he could start a new trend of sports astrology, and bettors will hire astrologers for their betting, and because he doesn't have it, bettors will consider these bets coincidental bets.
If he is that good, he can make money from betting. All I know is astrologers are getting paid to predict one's future.
The pay may be good, but it's way better if they can accurately predict the outcome of sports betting.