Wants to marry the daughter of his adopted brother
22/11/2018| IslamWeb
Respected sir,In Islam is it permited to marry a daughter of brother who exactly didnot got breast feeding by my mother?..but the brother of me was raisen by my father and mother as his parents left him.
Answer
All perfect praise be to Allah, The Lord of the Worlds. I testify that there is none worthy of worship except Allah, and that Muhammad 
is His slave and Messenger.
First of all, you should know that adoption is forbidden and whoever adopts a child does not become his real parent. Therefore, this man is not your brother, so it is permissible for you to marry his daughter.
Rather, this man should be traced back to his real father. If he does not know his real father; he could be given a general name like the son of 'Abdullah. Also, he is a non-Mahram to your mother, so she has to wear Hijab in front of him and she should not allow him to be in seclusion with her.
Allah Knows best.
Fatwa answered by: The Fatwa Center at Islamweb