You can read it as a BPD mother story, or as a postfeminism story (I'm thinking of this https://thepointmag.com/examined-life/among-the-post-feminists/). In both cases, it's feminine strategic helplessness.

A woman is walked out on by a husband and now can't walk. Her daughter takes care of her and no care of herself. They mortgage the house and go to a Spanish miracle doctor to unravel these knots. The doctor and the story are Lacanian, and it's some sort of late coming of age story for both characters. 

Ideologies are beliefs we try and make true, which try to make sense of reality but mostly mask it. Feminism is one of these, nowadays a bit weakened. Once one (a female one) stops believing in it, there are different strategies to adopt in the midst of an actually hostile society. These strategies are weapons, albeit defensive ones. 

One of them is admitting some sort of socially acceptable weakness, aka a chronic disease (the same way food stamps are some sort of socially acceptable universal basic income in the US, see TLP https://thelastpsychiatrist.com/2012/11/hipsters_on_food_stamps.html; disability might be playing the same role in France nowadays.). This is the mother's choice, whose feet are both numb and extra-sensitive, who can or can't walk, according to who is watching her.

Another strategy is to retreat into the traditional feminine role of a caregiver (after all, most women are still made and raised for this, despite the general effort towards equality of these last decades). This is the daughter’s choice: she can't do X or Y because she's taking care of someone who needs it, and never has she made a choice, she just moves into one of these prefab social roles. 

All this was triggered by a man walking out on them - a betrayal that reveals their weakness. The story goes on and confirms this fundamental masculine betrayal. In the end, there is no lesson. It's up to the characters to succumb or not to weakness.

Levy excels at the Lacanian stuff - everything is an echo about to make sense. I'm still mulling over what I've read.