When she was very young, her father died in an accident.
The pillar of the family crashed suddenly, leaving only the old, weak, sick, and disabled; her mother was young and didn't want to be dragged down by this broken family, so she made an excuse to go out to work and then disappeared without a trace.
Grandpa had a disability in his leg, which made it difficult for him to move around; he could only take on odd jobs at home, and Grandma had to look after the house, so she could only work various temporary jobs to earn a little money to help with the household.
They did have social welfare, but most of that money was spent on medicine year-round, leaving very little.
Despite living such a hard life, Grandpa and Grandma did their best to provide her with everything.