The message the story wanted to convey is very necessary but the long intro is not.  I am somehow confused and find the story strange because the sender did not ask the person who was receiving his BTC address when the sender was giving a big amount of money.

As far as I know, people who are sending funds always verify the account or address they are sending to regardless of whether they have already sent a previous transaction to that account.  I believe it was an SOP of any transaction.

It is true that a fund sent to an inaccessible Bitcoin address is forever lost.  So it is advised that we should always confirm the BTC address from the receiver.  And once it was confirmed then that would be the time we can execute the transaction.