According to Elder Uncle, why should the Yahi people not mourn for Timawi?

Immediately after his death, Ishi tells and re-tells the story of Timawi's death and the events leading up to his death. He recalls his bravery and his mistakes. After a while, however, Tushi begins to tell stories about Timawi's life. Eventually, no one speaks of the story of his death. Instead, they only talk about his hunting ability and his strength.