How is parallel structure shown in "Once upon a Time" by Nadine Gordimer?

Parallel structure is the use of matching grammatical structures within parts of a sentence or within neighboring sentences. Parallel structure can also include a repetition of larger elements in a work, such as events with similar outcomes described in a similar way. Gordimer uses both types of parallel structure in "Once upon a Time."
In the following sentence, note the repetition of prepositional phrases at the beginning.

In a house, in a suburb, in a city, there were a man and his wife who loved each other very much and were living happily ever after.

The next four sentences all begin with the words "they had."

They had a little boy, and they loved him very much. They had a cat and a dog that the little boy loved very much. They had a car and a caravan trailer for holidays, and a swimming-pool which was fenced so that the little boy and his playmates would not fall in and drown. They had a housemaid who was absolutely trustworthy and an itinerant gardener who was highly recommended by the neighbors.

The parallel structure accomplishes two things in the above passage. It creates a feeling of fairy-tale-like simplicity by the repetitive subject-verb opening of each sentence. In addition, it reinforces the privileged position of the family: "They had" many possessions, and "they  had" a prestigious social status.
Beyond the parallel structure in specific sentences and paragraphs, the bedtime story makes use of parallel structure as the rising action unfolds. The typical structure follows this pattern:
1. The couple takes an action to protect their wealth and position (joins Neighborhood Watch, installs electronic gates, installs window bars, builds the wall higher, and installs the Dragon's Teeth).
2. The couple hears reports of more robberies and social unrest.
3. The couple receives advice to increase their security.
4. The couple takes additional action to protect their wealth.
This cycle repeats three or four times in the story until it is broken (readers may hope) by the tragic death of the couple's son.
Gordimer uses parallel structure both within sentences and paragraphs and also within the bedtime story as a whole.
https://literarydevices.net/parallel-structure/