When children get a new toy to play,and if they find it interesting, they become addicted to it.The same is happening to your friend.The best thing you can do is to make him aware of the demerits of this addiction.Talk with him gently and politely so that he clearly understands what are you trying to explain. Make him feel that you are here to help him. By this addiction he will firstly, get bad grades in exams and with addition to this he'll go away and away from his close friends which will lead to unhappy and depressed state. If he doesn't realize conslt to his parents who can guide him and help him get out of this or simply let him to face the problems and realize his mistakes on his own.
I hope this helps you! Please mark as best if it helps you. Have a lovely day and Enjoy working on Brainly :)