By typing amir it says it is wrong. It could be excused since it is proper noun
Why's it he and not she?
here, the verb is " paRta" not "paRti"....
"He studies more than Aamir do"... isn't it correct?
This isn't natural in standard English, which is why it probably wasn't accepted. You could say 'He studies more than Aamir does' or 'He studies more than Aamir' and both would would work (in standard English).
Why not say "he studies much more than Aamir" because of the ज़्यादा