An old recipe that says “a little” may frustrate the next reader, yet that phrase can be the beginning of a good interview. Hand the original cook an empty spoon and ask what a little looked like in this particular dish. Sometimes the answer is a gesture rather than a number.
Keep the original line and place your observation beside it. Add the language in which it was said, the occasion and the date of the conversation. If the cook learned one version from a parent and changed it after moving cities, preserve both versions instead of quietly tidying the story into one.
For entries about illness, distinguish “this was offered in our house” from “this treats the illness.” The first is a memory you can document; the second requires evidence the notebook cannot supply. That distinction also leaves room for relatives who remember the same occasion differently.
Further reading: Ayurvedic medicine: evidence and safety (NCCIH)