The mistake you're making here is to approach this in the entirely reasonable belief that there are a set of established facts. Jack's story has no beginning, middle or end. Schrodinger's floofs abound. Often external opportunities can change the narrative quite dramatically, one day she's the Mummy Works Martyr bringing up her son alone, then I, Daniel Blake comes out and a stint on benefits being mistreated by the DWP becomes a better story. One day SB's dad is the best and most supportive co-parent anyone could want, the next she's flogging lightbulbs and toys to survive.