How did Warren Buffett survive the disaster of "Black Friday"?

On April 14, 2002, the new york stock market suffered a "Black Friday" crash, and Nasdaq technology stocks fell like a crash, especially the Internet stocks fell by more than half. Within a few days, the US stock market lost $2 trillion, and almost half of the wealth of new economic tycoons such as Bill Gates "evaporated", while Buffett's stock rose against the market and made a net profit of $570 million overnight, which forced people to start a new stove.