Question

your friend spends all time watching t.v

Answer 1

Encourage him to concentrate on studying more. 

Answer 2

watching tv overly leads to many problems. he can lose his ranks. he can damage his health.  he can loss a lot of time which is useful in his daily life. he is interested in watching tv so his parents should find which subject he is interested. if he was interested in current affairs , politics his parents have to make him to watch news chanels, if he was intrested in magics , factories , facts about animals, there lifestyle  his parents have to  make  him to watch discvery, history etc . so he cant lose his time & he can get more knowledge in the subject in which he is interested