It’s the objective case, i.e. everything that isn’t nominative, so this usage would be correct. We don’t have a real distinction between accusative and dative in modern english.
That being said, I’m a descriptivist who is strongly of the opinion that ‘who’ is always correct and ‘whom’ is archaic.
I’m also pretty certain that the stock would absolutely tank if he left.
He’s a fucking idiot, but the current valuation has zero basis in reality outside of his personality-cult. If that’s gone, all they are is a struggling mid-sized car company.