Well often it is a problem in server for his account, and he won't be able to get in his account.. if he is playing on mobile phone.. ofc. but give a try on emulator (program that you download on your computer and you can play on your PC all games that are for mobile phone) .. i play narcos cartel wars on my PC.. there are many emulators but i found "MEmu" the best.. just log into your google account there and download narcos.. connect with facebook (if his narcos acc is connected with facebook) and he will be able to play on his acc, but on PC.. (better late than never) ..
He could try re-installing he game, that could help. Or simply deleting the game, reset his iphone, and then again download the game..
As far as I am concerned the support won't give an answer to his questions and problems so give a try resetting an Iphone and downloading again. If that doesn't work, he could play on PC until they fix the problem (usually with next game update)