Yeah
, i can't understand how these scams work.
OK he is asking for an insane proportion of your inherited wealth (50%), but there's no request for bank details or for you to send any money to secure some kind of transaction.
What does he get from you replying "please proceed".
Knowledge that they've landed a potentially gullible target. They probably sent quite a few letters - it's not an unusual surname so I'm sure it wouldn't be difficult to get as many as it would be practical to contact by post.
The request for payment comes later, not at the beginning. The scam requires some degree of trust, so it's more efficient to send out many letters and concentrate on building sufficient trust only with people who reply. If you start straight off with a request for money or bank details you're unlikely to get a return. Maybe it would be worth trying it if you're sending many thousands of emails, but definitely not if you're sending dozens or maybe hundreds of physical letters. Once you've got a mark on the line and exchanged a few messages with them, that's when some payment becomes "unfortunately necessary". Perhaps an administration fee. A small amount, only a couple of hundred. The main reason for that is to get the mark financially involved. Once someone has spent money on something, they are much more likely to spend more money chasing success than to write off the money they've already spent. Perhaps then a bribe to a (completely fictional, of course) civil servant of some kind who has become suspicious. This person with a suspicion something dodgy is going on doesn't know how much money is involved because they're only a minor office worker or cleaner, so this helpful person in Hong Kong can buy their silence for only £5000 and they'll pay half themself. You're getting nearly $20,000,000...that's worth paying £2500 for, obviously. Etc, etc.
An add-on to this particular version of the scam is that it involves the mark in illegal activity. What are they going to do? Go to the police and say "Hello, I thought I was a partner in a $40 million fraud but it turns out that the other person was conning me. Please get me my money back." Probably not.