The marriage contract of two married non-Muslims who enter Islam
If a Kafir (disbeliever) and his wife accept Islam, whether Christians or otherwise, they do not have to renew their marriage contract; their former contract is acknowledged. (Part No. 19; Page No. 29) In the era of the Prophet (peace be upon him), the Kafirs and their wives used to accept Islam, and none of them was asked to renew their marriage contract. If the man is a true Muslim, there is no harm in offering Salah (Prayer) behind him. May Allah grant us success. May peace and blessings be upon our Prophet Muhammad, his family, and Companions.