how did Okonkwo father die?

Unoka was Okonkwo's father. Unoka died in debt and humiliation; the memory of him gives Okonkwo a terrible fear of failure. Unoka gets sick with a disease which causes his stomach to swell. This disease is considered an abomination to the earth so Unoka is not allowed to die at home, nor does ritual allow his body allowed to be buried. He dies and rots under a tree in the Evil Forest.