Well thats sad !!!!!!!! hehehe        sorry
Let us go with the answer

If ur frnd misses questions in exams there are several reasons 2 it. First of all he needs 2 concentrate on his writing speed for that he can solve sample papers which are easily available. And surely he must be stuck on some of the difficult questions so he should try and solve the questions first he seems 2 know and not waste his time in pondering those questions he dosen't know because if he does that he will be surely losing marks for the question he dosen't know and in addition for that too that he knows.

Hope it helps!!!!!!!!!!!!
You can suggest to him classes that help to improve writing and thus in this way he can overcome this problem. You must also ask him to maintain confidence within himself.