The transformation of the grandfather in this story is the key to answering this question. He starts off completely opposed to his son's marriage outside of his tribe, and cuts off all communication because he is unable to accept his son's wife. However, what manages to break through the impasse of his stubborness is the letter that his daughter-in-law sends to him about his grandsons and how they ask about him constantly. This triggers a massive internal conflict within him as he resolutely tries to ignore the thought of his grandchildren, but eventually has to admit defeat:
Okeke was trying hard not to think of his two grandsons. But he knew he was now fighting a losing battle. He tried to hum a favorite hymn but the pattering of large raindrops on the roof broke up the tune. His mind immediately returned to the children. How could he shut his door against them? By a curious mental process he imagined them standing, sad and forsaken, under the harsh angry weather—shut out from his house.
The pathetic fallacy of the weather and how he imagines his grandchildren to be trapped outside in this angry weather is of course a powerful symbol expressing his own stubborness and how his grandchildren are suffering as a result. What overcomes his tribal prejudice therefore is the thought of him dying without ever getting to know his grandchildren, and robbing both them and him the chance of enjoying a relationship together. The story ends with the grandfather's fear that already he might have left it too late.