Can he marry the daughter of a woman who was breastfed by his mother?

 

A woman was breastfed by my mother twice, and the one who was breastfed alongside her was my older sister. I had not been born yet. The woman who had been breastfed by my mother got married, and she has a daughter. Is it permissible for me to marry her (the daughter)?.

Praise be to Allaah.
 

 

If a woman
breastfeeds a child, then this child becomes her child through radaa’ah
(breastfeeding), and a brother through breastfeeding of all her children,
whether those children were there before him or came later. 

Based on
this, any woman who was breastfed by your mother is your sister through
breastfeeding, and you are a maternal uncle to all her children. So it is
haraam for you to marry her daughter, because you are her maternal uncle
through breastfeeding. And the Prophet (peace and blessings of Allaah
be upon him) said: “What becomes mahram (forbidden for marriage) through
breastfeeding is that which become mahram through blood ties.” Narrated by
al-Bukhaari, 2645; Muslim, 1447. 

It is haraam
for a maternal uncle through blood ties to marry his sister’s daughter, and
the same applies to the maternal uncle through breastfeeding. 

But it
should be noted that becoming a mahram through breastfeeding can only be
established through five well-known breastfeedings, because of the report
narrated by Muslim (1452) from ‘Aa’ishah who said: ““When the Qur’aan was
first revealed, the number of breast-feedings that would make a child a
relative (mahram) was ten, then this was abrogated and replaced with the
number of five which is well-known.” 

You state in
your question that this woman breastfed from your mother twice, so we should
note that the breastfeeding which makes the child a mahram is five
feedings. 

Ibn
al-Qayyim said in Zaad al-Ma’aad, 5/575: 

One
breastfeeding (rad’ah) means when the child takes the beast and starts
suckling, and then lets it go without being made to do so. That is one
breastfeeding, because the Lawgiver referred to one breastfeeding in general
terms, so it is to be interpreted according to custom, and this is the
custom. If the child stops briefly in order to breathe or to rest or because
of some distraction, then quickly goes back to the breast, this is regarded
as one breastfeeding, just as when a person who is eating pauses briefly
then quickly goes back to eating, this is not regarded as two meals, rather
it is one. This is the view of al-Shaafa’i.  And if the infant moves from
one breast to the other, this is one breastfeeding.  

See also
question no. 2864  

Thus it becomes clear
that the five breastfeedings could all take place in one sitting. 

If this
woman was breastfed by your mother five times in this sense, then it is not
permissible for you to marry her daughter, because you are her paternal
uncle through breastfeeding. If she was breastfed less than five times, that
does not mean that she is a mahram, so it is permissible for you to marry
her daughter. 

If there is
any doubt concerning the number of breastfeedings, whether it was five or
not, there is no proof of the child being a mahram in the case of doubt. 

Ibn Qudaamah
(may Allaah have mercy on him) said: 

If there is
any doubt as to whether breastfeeding took place or not, or with regard to
the number of breastfeedings, whether the number that makes the child a
mahram was completed or not, this does not make the child a mahram, because
the basic assumption is that he is not a mahram, and what is certain cannot
be dispelled by what is uncertain. 

See also
question no.
13357.

And Allaah
knows best.