It boggles my mind that people like this don't set up multi-sig wallets using hardware devices that are physically not in the same location.
In my experience, folks who dabble in crypto and even seasoned users always underestimate how hard and tricky of a problem proper self-custody actually is.
And when they do think about it, it's always too late.
And by the way, multi-sig is not the only thing you want to be thinking about.
Cold walletting is another that most people miss.
Also, avoiding concentrating a large number of coins on a small number of addresses (not that I know this was done in the cast of this scam) is another thing most people miss when in fact this was from day one listed as bad practice by IIRC Satoshi himself.
And finally, to mention the standard counter-argument to self-custody: the $5 pipe wrench attack only works if the attackers know the coins exist.
For those interested in plumbing the depth of the problem, the glacier protocol is a good place to start: