Big Sister.

This retro story is not about me. I never had a sister, neither older nor younger. I never lived in the country and no one walked me to and from school. But that's what it would have looked like to me. An older sister in my mother's absence replaces her. And she understands that and takes all the responsibility and care for herself.
The younger brother reluctantly accepts this reversal of roles. More doomfully than happily.
I know this firsthand. I had an older brother. Good thing he didn't care about me. He enjoyed beating me and I beat him. That's how boys grow up.
Still, having an older sister is much nicer than having a brother.