Answered by Sidi Tabraze Azam
Question: One of my relative is about to marry his father’s own brother’s daughter. Isn’t he a mahram to her? Aren’t they like brother and sister. Is it allowed in Islam?
Answer: Assalamu alaikum wa rahmatullahi wa barakatuh
I pray that you are well, insha’Allah.
It is permitted to marry one’s cousin. This is clear. [Mawsili, al-Mukhtar li’l Fatwa; Maydani, al-Lubab fi Sharh al-Kitab]
The scenario you mention seems to indicate that he is marrying his cousin. There is absolutely nothing wrong with that.
Examples from the Sunna
Examples from the sunna include that of the Prophet’s (Allah bless him and give him peace) marriage to Zaynab bint Jahsh (Allah be pleased with her), his cousin; and that of Sayyiduna Hanzala (Allah be pleased with him) who married his cousin Jamila bint Ibn Ubayy.
The upshot is that they are not considered like brother and sister. Far from it, rather, they are considered to be two unrelated people. He is not of the unmarriageable kin (mahram) for her; hence they would observe proper etiquette accordingly.
And Allah knows best.
Checked & Approved by Faraz Rabbani