The next day, my mom asked hmy sister if she remembered what my mom had said, but my sister said: no.

If you use too many pronouns it is confusing to remember who each pronoun refers to.

And tThen my mom repeated it again, and asked her again, but she still said: no.

It's usually repetitive to say "and then," in this case just "then" is enough.

So my mom started to teach her to count fingers, one word by one wordat a time, and told her that when she counted toreached the seventeenth word, she could find my father.