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 ; 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.