My 5 year old daughter is being taught French in school and she hardly remembers anything. Does it make sense to teach foreign language if the parent doesn't know the language?

You know what, kids are very good at picking up multiple languages, even though it may take time. Just like any other language, this too will need a lot of practice. My daughter also started learning French around the same age, even though me and hubby don't know a word of it! It was tough for her to remember at first, especially as it's something she doesn't use it in her daily life. But we helped her sit each day and study, as well as helped her learn the pronounciation through audio lessons. She's much at ease now. Just let her practice every day and give her time :)