sold my copy to a friend, having some difficulties

I haven't played Sins in a long time, so I sold my copy to a friend.  He originally told me the serial inside the book wasn't working (if it was in the case, I probably removed the sticker and put it in the book).  But what he really wanted was to get the updates for the game so I gave him my account info.  Understandably though, he wants the game under his own account name.  Is it possible to transfer it to his account somehow?