There is a moderate probability that he also has to pay taxes when he returns to Germany, so that would result in nearly the same price. It is a nice offer (
), but I am not sure if it is worth the risk.
Edit: Why don't you post your offer in the German board? I don't think that everybody who might be interested in this offer pays attention to the English part of the board.
Edit2: Note to myself: I will never ever post about taxes.