What is the ruling on advising against a reprehensible act if the one giving advice fears harm or anger from his parents?

There is no disagreement concerning the obligation to change the reprehensible (munkar), which is a collective obligation (fard kifayah) and may become an individual obligation (fard ayn) in some cases. Its levels are: by hand, and if one cannot, then by tongue, and if one cannot, then by heart, which is the weakest form of faith. No one has an excuse for neglecting to change the reprehensible with their heart. A Muslim should not fall short in fulfilling this obligation, according to its legal parameters, the most important of which are: that the denunciation does not lead to a greater reprehensible act, that the one denouncing has the capability, that one does not expose oneself to great tribulation, and that the reprehensible act is repelled by the easiest means possible. If any of these conditions are not met, the obligation is waived. If denouncing leads to a greater reprehensible act or a great tribulation, then changing it becomes forbidden. However, if it leads to a tribulation befalling the one denouncing, then the obligation is waived, and it remains a recommended act, and obedience to parents is prioritized here, unless the denunciation is an individually obligatory duty, in which case their obedience in abandoning it is not permissible.