Her husband divorced her; is his father still a mahram to her?
Question

                I married a woman and she lived with me for a while, then I divorced her and she married another man after me. She is asking whether it is permissible for her to meet my father after I divorced her, and to greet him with salaam.
Praise be to Allah.
      There is nothing 
      wrong with that, because Allah says (interpretation of the meaning):
      “Forbidden 
      to you (for marriage) are: ... The wives of your sons who (spring) from 
      your own loins,” 
      [an-Nisa’ 4:23]. 
      They are the wives of the sons, so if the son divorces her, she is still a 
      mahram to his father. 

    The mahram 
    connection between her and his father remains in effect. That is similar to 
    the case of the father’s wife; if the father divorces her, she is still a 
    mahram to the son. Allah, may He be exulted, says (interpretation of the 
    meaning): “And 
    marry not women whom your fathers married” 
    [an-Nisa’ 4:22]. 
    If his father divorces her, she remains a mahram to his sons. The same 
    applies to the wives of sons. End quote. 

    Shaykh ‘Abd 
    al-‘Azeez ibn Baaz (may Allah have mercy on him).