Maybe a naive take, but if there's one team in a large corporation that does not bend to "the CEO(-to-be) wants it", that is the Legal team. Particularly when the ask is a lawsuit of this scope and relevance, and potential costs (of all kinds). The head of Legal can just hint to the board how expensive (in all senses) the vendetta would be and the CEO is likely "not to be" anymore, or "to be temporary".