If he was breastfed by a woman, does her son become a mahram to his daughter?

 

My wife’s father was breastfed by his half-sister more than four times, so he is a mahram to her children, because he is her brother and because he was breastfed by her.


My question is: are his children mahrams to her children? 


Can his daughter, who is my wife, shake hands with his sons and uncover her hair in front of them or not?.

Praise be to Allaah.

If the wife’s father was breastfed by his sister and it was
five full breastfeedings within the first two years, then he becomes a son
to her through breastfeeding, and her children, both males and females,
become siblings to him through breastfeeding; they become paternal uncles
and aunts to his children through breastfeeding. Thus it is proven that
the relationship of mahram exists between them. 

The basic principle concerning that is the verse in which
Allah says (interpretation of the meaning):

“Forbidden to you (for marriage) are: your mothers, your
daughters, your sisters, your father’s sisters, your mother’s sisters, your
brother’s daughters, your sister’s daughters, your foster mothers who gave
you suck, your foster milk suckling sisters”

[al-Nisa’ 4:23]. 

So the daughter of a brother through blood ties is a mahram. 

And the Prophet (blessings
and peace of Allah be upon him) said: “What becomes mahram (forbidden for
marriage) through breastfeeding is that which becomes mahram through blood
ties.”

Narrated by al-Bukhaari, 2645; Muslim, 1447.. 

So the daughter of a brother through breastfeeding also
becomes a mahram. 

The scholars of the Standing Committee for Issuing Fatwas
said: 

The breastfeeding which establishes the relationship of
mahram is that which takes place five or more times in the first two years.
If the breastfeeding of the two brothers was like this, then they are
brothers through breastfeeding and the children of each of them are the
children of his brother through breastfeeding. … And it is not permissible
for one of them to marry the daughter of the other, because they are his
nieces (children of his brother) through breastfeeding. End quote. 

Fataawa al-Lajnah al-Daa’imah,
21/116 

Shaykh Ibn ‘Uthaymeen (may Allah have mercy on him) was
asked: 

I was breastfed with my maternal uncle by my grandmother –
who is his mother. Should my daughters observe hijab in front of him,
knowing that I was breastfed more than five times? 

He replied: 

If you were breastfed by your grandmother with five certain
breastfeedings, then you became a child to her, and her children are your
siblings, both the older and younger ones among them. If they became your
brothers, they became paternal uncles to your daughters. Based on that, it
is permissible for your daughters to uncover in front of all of their
maternal uncles. End quote. 

Liqa’ al-Baab al-Maftooh, 40/8 

Based on that, your wife may shake hands with the sons of
this woman and uncover her hair in front of them, because they are her
paternal uncles through breastfeeding. 

And Allah knows best.