It is an utterly staggering amount of money for one person to lose and still have far more wealth than the vast majority of humanity will ever know.
The largest loss of personal fortune is that of Elon Musk (South Africa), estimated by Forbes to be roughly $165 billion (£135B / €155B) as of December 2022.
https://www.guinnessworldrecords.com/world-records/94151-largest-loss-of-personal-fortune