It's a tough one. Speaking from bitter experience, if I were in your daughter's shoes I'd cling on to that full time job. Even if she's in the fortunate position of being able to find a position with school hours, she'll still probably need help with getting the child to and from school. There's rarely a neat solution.
If she gives up her job there's no guarantee she'll get back in once she's ready. Sadly it doesn't seem to work like that.
She could do casual work to make ends meet? I worked Saturdays and some evenings for a while; then as a cleaner during school hours. It wasn't a living though.
Most people I know had to cobble something together with friends, gps, reduced hours if they were lucky. The only ones who seemed to be able to get the balance right were those who had very senior professional jobs and guaranteed free childcare. .