Why has the narrator returned to her childhood home in "The Leap" by Louise Erdrich?

In the first paragraph, the narrator notes that her mother is sightless as a result of cataracts. Her mother was a trapeze artist in her younger days and this probably accounts for the graceful way her mother feels her way around the house and doesn't knock anything over. However, her mother loved to read as well and with no sight, she can no longer read. This is the biggest tangible reason the narrator returns to...

In the first paragraph, the narrator notes that her mother is sightless as a result of cataracts. Her mother was a trapeze artist in her younger days and this probably accounts for the graceful way her mother feels her way around the house and doesn't knock anything over. However, her mother loved to read as well and with no sight, she can no longer read. This is the biggest tangible reason the narrator returns to her home: 

Since my father's recent death, there is no one to read to her, which is why I returned, in fact, from my failed life where the land is flat. I came home to read to my mother, to read out loud, read long into the dark if I must, to read all night. 

The daughter mentions her "failed life," so this return is also somewhat of an escape or a retreat. But perhaps the largest motivating factor is that the narrator loves her mother and feels indebted to her. Note that the story is structured around the three times the narrator owes her life to her mother. The first instance is when her mother saves her own life in the trapeze accident and subsequently goes on living to eventually give birth to the narrator. The second is when her mother meets the narrator's father in the hospital. (This is the man who teaches the mother to read.) And the third time is when her mother saves the narrator from the fire with the aforementioned "leap." So, the narrator returns as a result of a failed life, but her main motivation is that she loves her mother and is gladly obliged to read to her.