I would suggest that it is better to opt for the MA. Political science than burning midnight oil in learning more about English language. (I don't understand the last sentence.)
Regarding the last sentence.
As he has done MA English, and wants to study further; he asks me in this regard whether he should do Mphil. in English language or MA political science. I am suggesting to my friend that he should go for doing MA political science than Mphill English.