I got a Management degree from McCombs. Aside from what comes with any degree from McCombs, it has been largely worthless. My intent in choosing that major (at 19) was, in fact, to be “a boss”. At that time they had several sub disciplines to choose from, one was entrepreneurship, one was organizational management, can’t remember the others. I chose entrepreneurship and got very very little out of those courses (although I was a very poor student).
To the OP, there’s a big difference between being the owner vs being an exec. If your son wants to be an owner, then he should get technical credentials in whatever field is most closely related to the kind of business he wants to own. That would likely be all he needs, but if he wants general business management expertise then he could add an MBA on top of it. If he wants to be an exec, then Finance is probably the best undergrad degree to get, and he’d be best served adding a JD, MBA, or CPA on top of that; if he wants to be an exec of a company in a certain industry, then again a technical degree related to that field for undergrad would possibly be better than Finance.