If a man divorces his wife before consummation of the marriage, she becomes haraam for all of his offspring
Question

                A man did the marriage contract with a woman, then he divorced her before consummating the marriage with her. Is she permissible for her son to marry after he has divorced her?
Praise be to Allah.
      No, if a man 
      divorces a woman, she becomes haraam for all of his sons, the sons of his 
      sons, and the sons of his daughters, because she was the wife of the 
      father, even if he did not consummate the marriage with her, and Allah has 
      not connected this matter to consummation of the marriage. Allah, may He 
      be glorified and exalted, says (interpretation of the meaning): 
      “And 
      marry not women whom your fathers married” 
      [an-Nisa’ 4:22]. 

    Marriage to their 
    fathers’ ex-wives is haraam for sons in all cases. “Father” in this case 
    refers to the immediate father as well as the grandfather, i.e., the 
    father’s father or the mother’s father. It includes all forefathers on the 
    mother’s side and on the father’s side. Their (ex-) wives are haraam for the 
    son to marry and he is a mahram to them because of the verse (interpretation 
    of the meaning): “And 
    marry not women whom your fathers married” 
    [an-Nisa’ 4:22]. 
    This includes the one with whom the marriage was consummated and the one 
    with whom it was not consummated. This is a matter concerning which there is 
    consensus among the scholars and there is no difference of opinion 
    concerning it. 

    The converse is 
    also true: The son’s wife is also haraam for father to marry in all cases, 
    even if the son did not consummate the marriage with her. If a man marries a 
    woman then dies before consummating the marriage with her, or he divorces 
    her before consummating the marriage with her, she is haraam for his father 
    and all of his grandfathers, because Allah says (interpretation of the 
    meaning) “the 
    wives of your sons who (spring) from your own loins” 
    [an-Nisa’ 4:23]; 
    He did not say those with whom you have consummated the marriage. End 
    quote. 

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