I don't think he will be commenting anytime soon again if this really is him
https://news.ycombinator.com/threads?id=il
like your neighbor being a serial killer or something
I think you are tad exaggerating here. not the dumbest but not certainly anything close to being competent. leaving keys in a cloud storage and not using OTC crypto exchanges outside US.
It's unbelievable stupid to use mixers on a public ledger because its all traceable and immutable. The really smart "criminals" DO NOT live in the US, especially NEW YORK out of all places, they DO NOT leave stupid social media posts or spend time chasing the vapid social media fame, they DO NOT use mixers because they are all points of surveillance.
I won't detail how one could've gotten away with this loot but there is an obvious hint here, blockchain is simply a means of temporary storage to move dirty money. Tether is largely considered a pipeline for illicit funds from China to move out to the West. They absolutely do not do any of the transactions on the blockchain, it is all done through highly organized criminal networks involving banks, shells, casinos.