Without a doubt, this is one the best books I have ever read. Although the author is a medical doctor, he possesses a special talent in writing. The story was very absorbing, engrossing, and riveting. I started the book one day around noon and I could not put it aside. I felt a strong urge to finish it as soon as possible and the next day, the book was over.The story in this book is so real as if somebody has gone through all these and is writing them. You can find all basic human emotions here together, love, hate, fear, friendship, betrayal, loyalty, selfishness, generosity, honor, piety, arrogance, deception etc.The two main characters in the story, Hassan and Amir, happen to be close friends, yet they have really distinct and different personalities. The one, who is more advantageous from almost all aspects over the other, Amir, is a superficial, unfaithful, coward boy. In my opinion, at the age of 38, he actually becomes a real man, i.e. a man of honor, righteousness and loyalty. The other character, Hassan, is genuinely, perhaps, the most decent human being you can ever come across out there. If you ever happened to have a friend like him, stick to him like you have no one in the World. He possesses all the good qualities that a human being may have, i.e. loyalty, courage, diligence, decency, integrity, faithfulness, you name it!This book is able to unearth all the humane feelings you might ever have lost and will enable you, by all means, to learn the meaning of being a genuine human being again. 

Question: How did you think about the sibling relationship?
Answer: He possesses all the good qualities that a human being may have , i.e. loyalty , courage , diligence , decency , integrity , faithfulness