USD usually goes up in a market crash though as people flee to safety.
Couple of things to note here. Druck is a disciple of Soros. Soros has made tens of millions by creating situations in countries that crash currencies. Let's use more accurate terms. Crash means devalue. Druck has made money on the coattails of Soros in the currency market when a currency is devalued.
What happens in currency markets is separate and apart for other markets. Other markets include the stock market, bond market, treasuries market, and commodities markets. Certainly there is movement between asset classes in changes of economic conditions. However, what I think you are referring to is that people move their money into cash - which in this country is USD. So if you look at a typical retail investor brokerage account, the investor closes positions in stocks (hopefully before a stock market crash) and then that money now sits in the account as cash - USD. That money needs to either stay as cash in the brokerage account or moved to some other bank account. Some will move to the 'safety' of bonds and treasuries. Few will try their hand at commodities and get their asses kicked. And others may try forex (currency) and really get their asses kicked. Their assumption is that the value of the USD will be going up against other currencies. I contend the exact opposite.
It has everything to do with how Soros and Druck made their money in the past. That is macro economic conditions are leading to the devaluing of USD. In simple terms, the USD buys less today than it did yesterday. In global terms, other currencies buy more USDs. Everyone knows this as inflation. However, there is more going on here. It hasn't been seen since the days of Jimmy Carter. That is stagflation - a combination of recession and inflation.
The US has been printing money for years. The amount of government spending right now is on steroids. And it seems with two infrastructure bills, that spending will even be greater. Which means more USD will be printed (digitized). The USD will be further devalued. I suspect it will crash. (Personal opinion, not investment advice.)
I will give you another piece of the puzzle. Big Banks (they trade stocks, bonds, treasuries, and currencies) will want to make a killing in all of this. The foreign exchange market is one of the least regulated markets in the world. It is also the largest - approaching $5 Trillion per day (yes, that is per day). That is enormous compared to every other market. Big Banks move the price of currencies, not retail investors. They move the price in the direction they want and when they want. It is for this reason that very few retail investors can make a living trading forex. I suspect that Big Banks will cash in on the devaluing of the USD. In fact, it will contribute to the devaluing of the USD. All they need is significant enough news to make the USD crash.
Let's look at this as it would appear on the surface. Economic indicators (unemployment, inflation, housing starts, prime lending rate, etc.) all suck at the same time. The fed can't sell enough treasuries to Japan and China. China is actually going broke right now. The fed starts a major round of quantitative easing (or what ever euphemism they use for printing money). Big Banks will acquire positions in USD from retail investors by stopping them out. Big Banks need the capital and positions for their big crash play. This is what I mean by Big Banks moving price when and where (direction) they want. (By the way, they do this all the time, just on a smaller scale.) Once Big Banks have their positions in place, they will crash the USD.
These are globalist pieces of $hit, that care not about the USD or the US economy and they care even less about American citizens.
All is needed is a combination of news to set things into motion. The number one contributor will be a stock market crash.
Now more on what this looks like and to clarify my original post. When I wrote sell USD short, I meant to enter positions in which the USD will lose it's value relative to other currencies. In forex, that depends on whether the USD is the quoted currency in a currency pair or the base currency. For instance, in the EURUSD (euro vs USD) the USD is the quoted currency. The USD is devalued when the price of EURUSD goes up. It take more USDs to buy euros. In the USDCHF (USD vs Swiss Franc) the quoted currency is the franc, the base currency is USD. The USD is devalued when the price of USDCHF goes down. It takes fewer francs to buy a USD. The trade to bet the crash of the USD is go long on EURUSD and go short on USDCHF. Both are shorting the USD without respect to a currency.
Here's a good video on understanding Big Banks.
Here's an interesting thing to monitor, IG Client Sentiment. Drill down on EURUSD. When retail forex investors go long on EURUSD, Big Banks drive the price short, and visa versa. It all there in historic charts. You will tangibly see how Big Banks manipulate markets - take price in the direction they want and when they want.