Timing the market is almost always a bad idea. If he had sold in March 2020, he almost certainly would not have bought back in until the market picked up again, losing out on a lot of market gains.
Monetary policy and stimulus during COVID caused a currency devaluation. If nothing else changes, the value of assets should increase, relative to a currency.
The same thing happened with monetary policy in March 2022. Interest rates went up, stocks went down.
I'm curious what others think.
But don't do it with more than 5-10% of your savings on one assumption/prediction.