What is the Muslim woman's duty towards her sister who hangs an amulet in her house, and what should she do?

Those who hang amulets in their homes or on their children to ward off misfortune, their situation is one of two: 1. Believing that the amulets are beneficial and effective in themselves: This is major shirk (polytheism) which expels its doer from the fold of Islam. 2. Believing that the amulets are merely a means to benefit, and Allah is the True Benefactor: This is minor shirk, as it leads to the heart becoming attached to them and can potentially drag one into major shirk.

This applies to amulets that are not from the Qur’an or prescribed adhkar (remembrances). However, if the amulet is from the Qur’an or prescribed adhkar, scholars have differed regarding the ruling on hanging them.

It is incumbent upon anyone who sees an unlawful amulet to denounce it and explain its danger. If it is from the Qur’an, its owner should be informed of the scholarly disagreement regarding it and that it is preferable to abandon it.