Her brother is in love with a divorced woman with whom he had a previous relationship
Question

                My brother in XXX  is in love with a girl, she is divorced with two kids(boy and a girl more then 4yrs), the love was between the two before the marriage but after the marriage made a wall in their love, after divorce they are more in love and plan to marry, not caring about the parents, the girl told my brother that, does he still believe in Allah?, as he had put him through so many test in life many And like 6 months ago my brother was saying he wont marry anyone except the girl he loves. First he wanted to get he acceptance of my mother and so. But suddenly a change came and now he doesnt care at all he is changed, his attitiude is quiet rude. My mother still is good with my brother but his attitude is bad. He is bad with my father. And I think there is a chance that the girl might have done some Amal(magic) on my family and my brother.

So is there a way we can know about wether there is some black magic done on my brother or not. As my father doesnt believe in Magic its hard for my father to find out a Aalim or a Mufti and get the issue solved. Also please make duaa for his good. He is not keeping in touch with me , the girl he loves is not liked by our whole family,and my brother before used to say that its not right to marry a girl without parents acceptance.
Praise be to Allah.
    I advise your father and the father of this woman not to 
    prevent this marriage, so long as there is no shar’i reason to prevent it. 
    If your brother loves this woman and she loves him, then it is in their 
    interests to get married. The Prophet  (peace and blessings of Allaah be 
    upon him) said: “There is nothing better for two people who are in love than 
    marriage,” i.e., if a man loves a woman and she loves him, then let them get 
    married, and that will calm them down and protect them from doing anything 
    haraam. Isn’t their getting married better for him, for her and for their 
    families than their falling into something that Allaah has forbidden? The 
    Prophet  (peace and blessings of Allaah be upon him) said, addressing 
    the guardians of women, if a man comes to propose marriage: “If there comes 
    to you one with whose religious commitment and character you are pleased, 
    then marry (your daughter) to him; if you do not do that then there will be 
    fitnah (tribulation) and widespread corruption on earth.” 

    But if there is a shar’i reason to prevent that, then our 
    advice to your brother is to obey his father and to remain chaste, and to 
    strive hard in doing so. The Prophet  (peace and blessings of Allaah be 
    upon him) said: “Whoever strives to be chaste, Allaah will help him to be 
    chaste,” i.e., whoever does his utmost to be chaste, Allaah will grant him 
    chastity and help him. Allaah says (interpretation of the meaning): 

    “As for those who strive hard in Us (Our Cause), We will 
    surely guide them to Our paths (i.e. Allaah’s religion — Islamic 
    Monotheism)” [al-‘Ankaboot 29:69]
And he should look for 
    another wife who will help him with his religious commitment and his worldly 
    interests. 

    With regard to witchcraft, if a person regularly reads 
    Qur’aan and recites the adhkaar that the Prophet  (peace and blessings 
    of Allaah be upon him) used to recite when going to sleep, when waking up, 
    in the morning and the evening and at other times and in other 
    circumstances, then he will protect himself thereby from the accursed 
    Shaytaan. The Prophet  (peace and blessings of Allaah be upon him) said: 
    “Allaah enjoined five things upon Yahya ibn Zakariyya, which he was to 
    follow and to enjoin upon the Children of Israel…” then he mentioned them, 
    among which was: “and He commands you to remember Him. The likeness of that 
    is of a man who is being pursued by his enemy, until he comes to a strong 
    fortress where he protects himself from them. Similarly a person cannot 
    protect himself against the Shaytaan with anything better than the 
    remembrance of Allaah (dhikr).” 

    Al-Mi’wadhaat (soorahs seeking protection with Allaah) are 
    among the greatest things by means of which a person may protect himself 
    against witchcraft, so recite them in the morning and in the evening, after 
    every prayer and before going to sleep. 

    Make a lot of du’aa’ for your brother, that Allaah may guide 
    him and grant him wisdom. And Allaah knows best.