What are the conditions required by a US bank to withdraw an international wire transfer?

A friend of mine was probably close to being defrauded (he is a painter, someone sent him a document certifying that he did a wire transfer to his bank for three painting he wants to buy, asked for some shady "transport arrangements" right away yada yada yada).

I told him that this is very likely to be a scam and so that he does not do anything before seeing the money on his account. We are French, the "customer" is "American"

My question the following: under which conditions would a US bank accept a request from a customer of theirs to withdraw a wire transfer said customer did to a foreign bank?

In other words: how easy would it be for the "customer" of my friend to get his money back, once they manded on my friend’s account?