How can someone hold that kind of money in a centralised exchange? Not to be harsh, but the person typically got what he deserved. Coinbase is one of the exchanges that can easily freeze users funds once they suspect anything or the 3-letter government agencies ask them to do it.
Even if you want to hold money in a self-custodial wallet, it shouldn't be centralised tokens/coins. The worst of it is tether; they can freeze your fund while it's in your private wallet immediately. The government asks them to do that because they are fully open to obeying and taking orders from them.
I believe we've all encountered whales or huge transactions on exchanges as well, Binance, Coinbase etc. have an extravagant amount of daily transactions and a huge volume of Bitcoin and altcoins. It would be a mistake to assume that investors do not leave large amounts of crypto in exchanges, just because it's not generally advisable. According to the video, the frozen funds are due to suspicions of fraud or money laundering, even though there are no charges being made.
This proves the importancy of using decentralized wallets, as the governments may even freeze your funds with no particular charge.