The name of the hacker is a bit on the nose lol.
I can't understand how you could let this happen. If they stored everything in fat hot wallets, that just seems like a recipe for disaster. Especially with the "features" of crypto. Math for the most part, doesn't care about your feelings, or money for that matter.
Hot vs Cold wallets are a social construct. People talk about wallets being "online" or "offline" but if the keys are compromised there's no such thing.