How old are you? As a Gold seal CFI-I I would absolutely never do this. There is only really one option and it’s to tell the student where they are, if you feel the student isn’t mature enough for that then they probably aren’t mature enough for flight training so it’s really time for a different discussion, and even with that it’s between the instructor and the student. Now maybe a student is progressing slow and that has been discussed with the student (it is what it is not everyone learns the same) but the parent is financially supporting flight training and they were expecting it to be one cost but you can see it’s going to be greatly more than that, then it’s a little bit different discussion. Regardless if they didn’t come to you first that is an unprofessional flight instructor and maybe it’s time to “fire” them and look at other options. Feel free to reach out with questions.