What is the ruling on exposing a person who claims to be a Sheikh and a scholar, and who has a Quranic school where he teaches erroneous Fiqh and permits eyebrow plucking (namṣ), and how should one deal with him, given that he is followed and respected by the majority of people?

In such matters, one must refer to reliable scholars. A person's error in one issue does not necessitate warning against them if their good outweighs their bad; rather, they should be advised and shown what is correct. The issue of plucking eyebrows (al-namṣ) involves a difference of opinion among scholars. If one adopts a valid opinion, they are not to be blamed. One should not rush to judge a person as deviant except with clear evidence and the testimony of trustworthy scholars. When their deviation is confirmed, one may warn against them, while considering the benefits and harms.