Funny, he is building on an unstable land, near seashore.
Did he consulted a geologist?
What about the sea rises?
The bunkers will not protect him from ground collapse or sea rises.
It seems to me he is the unwise man building on sand.
Smartest guy in tech: I live on an island. I am building a basement to escape to.
All that is fine. He just has to worry about not making it big or the island may capsize.