When his father died, Si Boyi was still a young boy, only aware that his mother had fainted from crying, and the adults had brought him and Xiaohui to the village head's house.
Only later, when they were in mourning, did he realise his father had passed away. As for how he died, Si Boyi didn't know. He was afraid to ask when he was young, and as he grew up, he didn't want to upset his mother, so he never asked. In his understanding, he had always thought his father had died from an illness.
Because before his father's death, all Si Boyi could remember was his father lying in bed all day long, needing help with eating, drinking, and relieving himself, giving off the impression of being seriously ill.
Not until this moment, did Si Boyi realize that his father had actually committed suicide. He simply could not understand why his father would have fallen from the second floor of the hospital. Why would a robust man choose suicide?