One supposes a man such as him would be able to accept death with equanimity. This is backwards. As he was losing much more in death than most of us will; he was far more alive than most anyone has ever been.
Kurt Gödel starved to death because of fear of dying poisoned.
In bad times, intelligence by itself is probably not enough to save us of our emotions.
Just to add that Feynman's last words are reported to be "I'd hate to die twice — it's so boring".