He mistreats and ignores his wife’s mother
Question

                Is it permissible for a man to cut off ties with his mother-in-law, or to raise his voice to her or insult her? Please explain with quotations of verses from the Qur’aan or ahaadeeth of the Prophet (peace and blessings of Allaah be upon him), as this matter is of great concern to me. Please note that my sister is married and her husband causes a lot of problems for us as he always argues with my mother, his wife’s mother.
Praise be to Allah.
    The husband should treat his wife’s relatives well, 
    especially her mother, because that will lead to love and harmony, and a 
    stable married life. If the husband honours his mother-in-law he is in fact 
    honouring his wife and honouring the grandmother of his children. If he 
    mistreats her then he is mistreating his wife and his children, and is 
    failing to provide the kind treatment that Allaah has enjoined. Allaah says 
    (interpretation of the meaning): 

    “and live with them honourably”

    [al-Nisa’ 4:19] 

    “And they (women) have rights (over their husbands as 
    regards living expenses) similar (to those of their husbands) over them (as 
    regards obedience and respect) to what is reasonable, but men have a degree 
    (of responsibility) over them. And Allaah is All-Mighty, All-Wise”

    [al-Baqarah 2:228]

    And the Prophet  (peace and blessings of Allaah be upon 
    him) said: “The best of you is the one who is best to his wife, and I am the 
    best of you to my wives.” Narrated by al-Tirmidhi (3895) and Ibn Maajah 
    (1977); classed as saheeh by al-Albaani in Saheeh al-Tirmidhi. 

    Think about how the Prophet  (peace and blessings of 
    Allaah be upon him) was. He used to honour the friends of Khadeejah (may 
    Allaah be pleased with her) even after she died. This supports what we have 
    said, that honouring the relatives and friends of one’s wife is honouring 
    her. 

    Muslim (2435) narrated that ‘Aa’ishah (may Allaah be pleased 
    with her) said: I never felt jealous of any of the wives of the Prophet (S) 
    except Khadeejah, even though I never met her. She said: When the Messenger 
    of Allaah (S) slaughtered a sheep, he said: “Send this to the friends of 
    Khadeejah.” I annoyed him one day and by saying: Khadeejah? The Messenger of 
    Allaah (S) said: “Her love is instilled in my heart.” 

    Muslim also narrated (2437) that ‘Aa’ishah (may Allaah be 
    pleased with her) said: Haalah bint Khuwaylid, the sister of Khadeejah, 
    asked permission to enter upon the Messenger of Allaah (S), and he 
    remembered how Khadeejah used to ask permission, and he felt happy when he 
    heard that. He said: “O Allaah, Haalah bint Khuwaylid.” 

    As for insulting and raising one’s voice, this is the 
    opposite of kind treatment, rather it is a kind of sin as it is not 
    permissible for a Muslim to insult a fellow-Muslim. 

    Similarly, cutting off ties and ignoring others is forbidden 
    in Islam. Al-Bukhaari (6077) and Muslim (2560) narrated from Abu Ayyoob 
    al-Ansaari (may Allaah be pleased with him) that the Messenger of Allaah 
     (peace and blessings of Allaah be upon him) said: “It is not 
    permissible for a Muslim to forsake his brother for more than three days, 
    each of them turning away from the other when they meet. The better of them 
    is the first to greet the other with salaam.” 

    This husband has to fear Allaah and treat his wife and her 
    relatives well, so as to increase love and harmony and so that Allaah will 
    bless his family, home and children for him. 

    And Allaah knows best.