Make sure they are on track to be financially independent, at all, by standard retirement. If they are age 60 and have yet to save a dime, like one of my coworkers, a FIRE discussion is not productive. If the student is not ready, the teacher needs to move on.
Second, do they really want to stop what they are doing early? I think most people think they want to quit, but I hope there are maybe 20% of folks out there that love, or at least like, what they do, and have no desire to stop soon.