He can contact his bank to make a claim, they will request it from the receiving bank, and if everything is clean as he is claiming, money should return into his hands.
But as we can see here, with so many posts made, he never gave any details.....
I wont comment other bullshit here, but this is just ridiculous that you are trying to lie here to people who do not know much about bank transfers. (SEPA bank transfers which are in €, I am not commenting in any other bank transfers in which I am not so experienced)
Yes he can contact with his bank and make a claim. After that they will request payment back from receiving bank. (All correct)
Here it is going wrong and you are lying. It does not matter if money is clean or not, receiving bank owner can deny any request.
Which means that money wont be refunded. Bank cannot take money from your account on their own and refund to this user. They will ask permission from you and they need your agreement. (This is confirmed by EU law)
It will be different case if the money is fraudulent and they have a police order.
About your claim that bank seized that money or refunded.. Why you are not posting any evidence here showing that 26k did not move to anywhere else? Why do you not back up your claim with evidence?
Why did you offer him monthly repayment when you already know that his money was fraudulent?
Your story does not add up at all and are full of lies.