In The Kite Runner, why do you think Rahim Khan went to find Hassan and invite him to come live with him in Baba's house once more?

 In the book The Kite Runner Rahim
Kahn had been best friends with Baba and Amir.  After Baba had escaped to Americahe had
asked Rahim to keep care of his place.  Rahim is also aware that Hassan is Baba's son.

When Hassan was a child Rahim Kahn had watched him grow up
and knew that he deserved to have more.  However, he was also aware hat the boy could
not get his fair due because he was born illegitimately from a Hazara woman. 

Rahim Kahan was the one Hassan had told about his rape as
a child.  Rakim is left alone and older and I believe that he wants to give something to
Hassan.  He wants him to come and stay in the big house, but Hassan will not do it.  He
is very honorable and will only stay in the house in which he was born on the property. 
Through bringing Hassan back Rakim Kahn gains a family as well.