Her Husband Suckled from her Mother
19-4-2018 | IslamWeb
Question:
I kindly Ask you to answear my question as a whole family depensds on finding this problem out. Almost 30 years ago a sister married against her fathers will. The reason was that the brother she wanted to marry had been breastfed by her mother more than five times, as she used to babysit him. However, her father had no witness for this statement, as her mother had passed away, and his family swore by the Quran it had not happened. The local imam therefore became her wali and she married and cut off her father and siblings off for many years. Now she has contacted her brothers and wants to get back in touch. Her father therefore contaced the local imam and he said she is living in zina and he should forget his daughther as she is in big sin if she does not divorce him. Her brothers however wants to get back in touch with her, but would like to know what sharia says about this matter. She has several childeren with this man now. What should they advice her to do?
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.
Breastfeeding is not proven based on the testimony of one man. We have not come across any disagreement among the scholars on this issue. However, there is a difference of opinion about accepting the testimony of one woman.
It was more appropriate for this woman to avoid marrying that man to be on the safe side.
Ibn Hajar wrote in his book Fat-h Al-Baari that 'Umar 
said: “Separate between them (a married couple) if there is any evidence [proven they are suckling siblings]; otherwise leave the men and the woman [remain married], unless they want to be on the safe side.” So, avoiding it (in order to be on the safe side) is because of having a doubt.
Now let us look at the fact of her marrying that man without the permission of her guardian. There is a disagreement among the jurists about this case, as well. The majority of the scholars are of the view that it is a void marriage, contrarily to Abu Haneefah, who is of the view that it is valid.
The view we adopt here in Islamweb is the view of the majority of the scholars, but we see that there is nothing wrong in acting according to the view of Abu Haneefah and ruling that the marriage is valid, especially that they have been married for a very long time now.
Acting according to the concession when needed in order to repel difficulty and harm is something that some scholars said to be permissible. So, this woman is not considered as committing Zina with that man, and if she had children from him, they are traced back to their father.
Therefore, her father and her brothers must keep ties with her, because she is among the relatives that one must keep ties with and it is forbidden to cut ties with her.
Allah knows best.