Watching tv all the time can be harmful in many ways.If he spends his all tie only seeing tv then he will lose his marks. He can also damage his health he will lose a lot of useful time . His parents should make him watch news channels and other educational programmes like discovery, national geographic which gives new and amazing facts . make him aware of what problems he can face due to this. By encouraging him to read good books and study when he is free.He should make some interest in studying so that he can give up this bad habit and use his time in a better way by gaining more knowledge.