What causes Bakha to tell his father about his morning's misadventures, and how does his father react?

Lakha is unusually gentle and sympathetic when he asks Bakha what is bothering him. This unaccustomed sympathy causes Bakha to risk sharing the traumatic events with his father--but Lakha reacts by blaming Bakha and telling him that he must obey and respect people in the castes above him.