Several weeks? How do you predict the markets tanking weeks in advance? If anything he was smart and we were the ones in denial. Besodes most senators are morons and take advice. If anything he had a shrewed broker who advised him to dump hos stock.
You don't have to predict ANYTHING when you're in a position to influence things. Sell first, then tell a bunch of business leaders it's "akin to the 1918 pandemic". Keep that up and it's a sure bet you've made the right move (and set yourself up to make a bundle when it's time to get back in).
https://www.newsobserver.com/news/coronavirus/article241330126.html