The short story "In the Wheels" (available in full at that link, perhaps a 10-15 minute read) is mostly about car racing with a speculative-fiction twist, but there's a surprising (to me) ending for the protagonist, initially a teenager living with his father, "Firstmother", and his father's young second wife Sara. The following quote is from near the end of the story:
Father died a year later. Firstmother crumpled up with grief and followed him into the grave in six months. Sara’s still a young woman, and she makes a good wife. My brothers and sisters that were her children have become my sons and daughters. Sara’s pregnant with the first of mine, and it looks like I won’t need a secondmother for many years.
Why did the author include this part - what does it add to the development or analysis of the character (or of the setting)? After what happened with the races, I could have imagined the protagonist either continuing life as a racer or settling down to a "normal" life like his father, perhaps marrying a local girl, but marrying his stepmother after his father's death? That was unexpected to me, and I don't understand the purpose of it with regard to the story.