In real life, Major League Baseball would never allow Billy to manage the Twins

And no, it isn't just because of the obvious (he's underage). What I mean is what I would call "The Ted Turner rule". Back in 1977, Turner made himself the manager of the Atlanta Braves for a day before the commissioner and president of the National League demanded that he step aside. Simply put, they told Turner that it was forbidden for anybody who owned a stock in a Major League Baseball franchise to manage it.

https://www.espn.com/blog/playbook/fandom/post/_/id/22066/the-night-ted-turner-managed-the-braves

https://www.atlantamagazine.com/news-culture-articles/flashback-that-one-time-ted-turner-coached-the-braves/

https://www.mlb.com/cut4/38-years-ago-then-braves-owner-ted-turner-decided-to-manage-his-own-team-for-a-game/c-123387944

https://www.thebiglead.com/posts/braves-owner-ted-turner-manages-this-day-in-sports-history-01e7zj4jzk87