I am not a CEO, but I am pretty sure that after the company becomes a national entity there are some specific insurances specialized for this kind of individual and the board provides some security at company expenses [1].

For instance: The shareholders of Tesla know that it has a huge dependency on the services of Elon Musk, and the continuity and value of the business rely upon his ability to work (i.e. not being dead); I strongly believe that if the board of directors does not allocate security services to keep the continuity of his life (i.e. to keep him working) I would be surprised that it wouldn't be a gross breach in their fiduciary duties.

[1] - https://fortune.com/2024/09/14/tech-billionaire-ceos-securit...

[2] - https://www.sec.gov/Archives/edgar/data/1318605/000119312510...