Q. A lady in my community wishes to leave for Umrah with her foster-sister’s son. Both sisters were breastfed by one woman. Is it permissible for her to go for Umrah taking her foster nephew as her Mahram?
A. Your foster-sister’s son is considered to be your foster-nephew. Accordingly, your foster-nephew is a Mahram to you and hence, he can accompany you as your Mahram for the purpose of Umrah. (Mahmoodiyyah 17/40)
Allah Ta’ala Knows Best
Mufti Ismaeel Bassa
This answer was collected from TheMufti.com, which is a fatwa portal managed by Mufti Ismaeel Bassa from South Africa.