Directors have a fiduciary duty to the shareholders and that includes a legal liability if they don’t do their job. That said if the chairman has a controlling majority of the shares they can run the company into the ground if they want to as it’s their money to waste.

Generally if you want to bring investment into a company it will come with strings attached like nominated seats on the board of directors to prevent this sort of thing. Voting shares can be different normal shares or there can be several share types with different levels of voting rights. However the structure of the shares will be disclosed to the board and for a publicly traded company this will be public.