The board is supposed to act in the interest of _all_ shareholders, not just majority or controlling. Meaning, a group of minority shareholders could sue for discrimination as happened at Tesla recently.

Also, I’m not sure of the ownership structure, but he may own 57% of voting stock but a minority of non voting stock, and the non-voting members may have certain rights irrespective of voting rights. I’d be shocked if they didn’t negotiate some kind of escape hatch.