Is it permissible for an elderly woman who no longer has a desire for marriage to marry a man who has four other wives
with the intention of being provided for? Can she be considered a fifth wife, thus becoming impermissible?
It is impermissible for a Muslim to marry a fifth wife, whether she has or not any desire to marry. There are legal proofs mentioned in this regard. May Allah grant us success. May peace and blessings be upon our Prophet Muhammad, his family, and Companions.