If your friend lives near you, the best solution would probably be to copy your downloaded version of the game over to a USB drive and loan it to him. Otherwise you can use the
old outdated (Thread) to
download the game (Torrent). Keep in mind you need to change the realmlist information to connect to the correct server. Nostalrius does have a handy file that does this automatically for you which you can
download here (Bat file)P.S: Delete the WTF and WDB folder if there is one when you've installed the game.