You can always write him back, offer him a million dollars to call of the hit, and ask for his bank account number to wire him the money.

Later, you can mail him, to notify him that he is the lucky UK Lottery winner.

Then after that, you can inform him that his relative, Maria Maria Gonzalez Romero Hernadez Martinez has past away and left all of her money to him, but once again, you will need that account number to transfer the funds.