Who is real father of Tengo?
Tengo always feel NSK fee collector is not his real father because he was very hard on him. He desperately want the answer to this question. He wants to know from where he comes from. NSK fee collector was an average guy. His only achievement was that he was good at collecting fee. On the other hand Tengo was more good looking, smart, with lot of achievements in music, studies and games. This made Tengo feel that Mr. Kawana is not his real father. Plus that dizzy spell make him sure that his father is someone else. When Tengo asked Mr. Kawana that who was he? His father said,”you are nothing.”
When his father was in coma he realize may be whatever happened was good for him(Tengo). It was quite hard for a child but ultimately it made Tengo strong. Towards the end Tengo fulfill all his duties towards his father by heart. He took care of his father so well that the question of his real father became irrelevant. May be that is the reason Murakami doesn’t answer this question.