Divorcing a wife because of her bad attitude
Question

                My brother-in-law had a miserable married life for last two years. his wife used to behave badly with him and the worst thing the girl used to torture /abuse her mother-in-law .

After many tormenting and disgusting discussions the boy,his mother, his father and his sister decided divorce is the only solution and he divorced. Please clarify whether the stance taken was right or not? .
Praise be to Allah.The basic principle concerning divorce is 
    that it is makrooh. This is indicated by the words of Allaah (interpretation of the meaning): 
“Those who take an oath not to have sexual relation with their wives must wait for four months, 
    then if they return (change their idea in this period), verily, Allaah is Oft-Forgiving, Most Merciful.
227. And if they decide upon divorce, then 
    Allaah is All-Hearer, All-Knower”
[al-Baqarah 2:226]
With regard to the oath not to have sexual 
    relations, Allaah says “Oft-Forgiving, Most Merciful”, but with regard to divorce, He says, “All-Hearer, All-Knower”. This contains 
    an element of warning, and this indicates that divorce is makrooh or disliked by Allaah. 
But there may be some situations in which there is no alternative to divorce, and matters 
    may reach a point where divorce becomes essential. In a situation such as that mentioned in the question, divorce is an appropriate solution, 
    because one of the rights that a husband has over his wife is that she should respect his family, especially the husband’s mother. The mother’s 
    rights over a man come before his wife’s rights, so the wife should help her husband to honour his mother. 
The scholars (may Allaah have mercy on them) have stated that divorce is permissible in 
    cases where it is needed because of the wife’s bad attitude and bad conduct and because she is causing too much harm and not doing what she is 
    supposed to do.  
Al-Mughni, 
    10/324 
And Allaah knows best.