My main concern is the possibility of new one being blocked, which is why I haven't taken the old one online. So I'll have him check it if its still registered on his name. If not, I'll have him contact customer support first and see what they have to say and return it if they suggest so.
Maybe I should ask Amazon for a reward for fixing the old one.
AFAIK they'll refund the return shipping costs (please correct me if I am wrong), so it shouldn't be a problem.