Not sure what problem he is having, but my problem is as follows :
Got mine working now, but missus copy does the following, launcher starts up, set on EU , play button showing, she has an ESO EU folder. Theres a pause for a couple of seconds after the launcher starts up , then it comes up with a window which says "already downloading". Clicking play causes nothing to happen, game doesnt launch. Have repaired twice now, nothing changed.
Have you tried skipping the launcher all together and loading the game with the .exe?