I don't think it'll workout even if he does know the score before the sportsbook updates. Sportsbooks(at least the major ones) are extremely quick to iron out the delays in score updating as well as block the bets while the point is ongoing. A few times it does happen when they are delayed to block but its fairly rare. If it does happen with a substantial amount being wagered, they usually just void the bet.

That being said, most sportsbooks don't want a customer who's consistently winning. They'll restrict the betting sections if needed to not lose out on potential profits.

final verdict: It's possible once in a blue moon with low stakes but in the end, they'll catch on the trend and either restrict the wagers or remove the selections completely.