Is the wife of one’s son through breastfeeding a mahram?

The wife of a son of one’s loins is a mahram to his father,
because Allaah says (interpretation of the meaning): 

“Forbidden to you (for marriage) are… the wives of your
sons who (spring) from your own loins”

[al-Nisa’ 4:23]

If a man has a son who is married to a woman, his father
becomes a mahram to her, and he may travel with her, be alone with her, look
at her face, and so on. With regard to his son through breastfeeding, most
of the scholars are of the view that he is like a son from his own loins,
but Shaykh al-Islam Ibn Taymiyah rejected that and said: Breastfeeding does
not affect the in-law relationship; the wife of a son through breastfeeding
is a non-mahram to the father, so she should not uncover in front of him and
she should not be alone with him and he may not travel with her, because she
is a stranger (non-mahram) to him. Allaah says (interpretation of the
meaning):

“Forbidden to you (for marriage) are… the wives of your
sons who (spring) from your own loins”

[al-Nisa’ 4:23]

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.”

A son’s wife is not a
mahram to his father because of blood ties but rather through marriage.
There is no blood tie between his father and her, rather she is his mahram
through marriage. This is the view favoured by Shaykh al-Islam Ibn Taymiyah,
and this is what I think is correct.