It's possible but it's extremely dangerous. The exchanges that you'd use to short Tether are the ones preventing Tether from collapsing. These exchanges could invent an excuse to liquidate you before they allow Tether to collapse so even if you were right you'd still lose all your money.
Still his reason to make that bet was the comedy of being proven right about how broken crypto is when he lost his money. And not for the opportunity to be proven right and make money.
I believe something very similar to the above commenter, with the proviso that it might not be "the exchanges" engaged in market manipulation but rather Tether or a co-conspirator. Tether has printed trades far above a dollar before on various exchanges; the only reason to waste money doing that (as the buyer) is to liquidate shorts. Playing in a rigged casino seems even more -EV than playing in a fair one. But this is not top of mind or hugely relevant to the comedy gold thread.