He committed adultery with a woman and she married someone else, and the adulterer wants to marry her
Question

                I am in a dilemma  . I was contacted by a brother from my home ('muslim') country who had a relationship with a relative of mine  (and he informed me of this just now as i had no knowledge of it beforehand) and he claims that they had zina and she may be expecting his baby soon.  He was supposed to marry her soon.  Recently she was married to someone else and she is here in XXX presently.  The brother who contacted me was shocked when he returned from business trip and discovered this.  He wishes for me to allow him to contact her, and I wish to advise him to forget her and to repent as she has been playing with him for past couple of years.  She also played with me for a while before Allah guided me.  I dont think any of the above-mentioned people are practising the deen, probably dont even pray.  What would be the responsible and islamic thing for me to do - and should i consult any others?
Praise be to Allah.
    Your question includes a number of serious issues, not just 
    one problem.  The details are as follows: 

    1 – The neglect of prayer on the part of your friend and your 
    relative, who claim to be Muslims. This action is kufr. See Question no.
    5208 and 2182. 
    Indeed, you say that they do not practise Islam, and this is disaster upon 
    disaster, kufr upon kufr. We seek refuge with Allaah from that. 

    2 – Falling into zina (fornication, adultery), which is 
    forbidden in Islam, as is well known. It is forbidden even in the other 
    divinely-revealed religions. 

    3 – Marrying an adulteress when she is pregnant as a result 
    of zina. 

    4 – The adulterer seeking to marry an adulteress after she 
    has gotten married to someone else. 

    Which disaster should we begin with? Which question should we 
    answer? Laa hawla wa laa quwwata illa Billaah (there is no power and 
    no strength except with Allaah). 

    Let us start with the most serious: 
1 – Kufr as a result of 
    not praying and neglecting all the rituals of Islam. 

    There is no doubt that kufr (disbelief) dooms one to enter 
    Hell, Allaah says describing the mushrikeen and how they will answer 
    concerning the reason why they entered Hell: 
“They will say: ‘We were 
    not of those who used to offer the Salaah (prayers), 

    Nor we used to feed Al‑Miskeen (the poor);

    And we used to talk falsehood (all that which Allaah 
    hated) with vain talkers.

    And we used to belie the Day of Recompense, 
    

    Until there came to us (the death) that is certain’”

    [al-Muddaththir 74:43-47 – interpretation of the meaning]

    Ibn Katheer said, commenting on this passage: 

    “ ‘We were not of those who used to offer the Salaah 
    (prayers)’ means ,we did not worship our Lord. 

    ‘Nor we used to feed Al‑Miskeen (the 
    poor)’ means, we did not show any kindness to His 
    creation of our own kind (our fellow human beings). 

    ‘And we used to talk falsehood (all that which Allaah 
    hated) with vain talkers’ means, we used to speak of that of which we 
    had no knowledge. Qutaadah said: (it means), everyone who went astray, we 
    followed him. 

    ‘And we used to belie the Day of Recompense’. Ibn 
    Jareer said: we used to deny the Day of Recompense, of reward and 
    punishment; we did not believe in reward, punishment or reckoning. 

    ‘Until there came to us (the death) that is certain’ 
    means death, as in the aayah, ‘And worship your 
    Lord until there comes unto you the certainty (i.e. death)’ [al-Hijr 15:99].” 

    But what you have to do is to advise them, establish proof 
    against them and explain to them that what they are doing is destroying the 
    most important pillar of Islam, so they must hasten to repent from 
    neglecting the prayer and all the rituals of Islam. It is not permissible 
    for you to turn a blind eye to one who neglects prayer under any 
    circumstances. Start by advising and guiding him, then shun him and turn 
    away from him, do not greet him, eat his food or sit with him, if that will 
    do him some good. Make him aware of how great his sin is, so that perhaps he 
    will turn back to his Lord and repent.  

    2 – Falling into zina (adultery) is a major sin. Allaah says 
    (interpretation of the meaning): 

    “And come not near to unlawful sex. Verily, it is a 
    Faahishah (i.e. anything that transgresses its limits: a great sin, and an 
    evil way that leads one to hell unless Allaah Forgives him)”

    [al-Isra’ 15:32]

    The Prophet  (peace and blessings of Allaah be upon him) 
    said, “An adulterer, at the time he is committing illegal sexual intercourse 
    is not a believer; and a drinker, at the time he imbibes an alcoholic drink 
    is not a believer; and a thief, at the time of stealing, is not a believer. 
    And a robber  who robs (takes illegally something by force) while the people 
    are looking at him, is not a believer at the time he is robbing (taking).” 
    (Narrated by al-Bukhaari, no. 2475). 

    It is a major sin, and the one who commits this sin is issued 
    with a warning of a painful torment. It says in the great hadeeth about the 
    Mi’raaj (Prophet’s ascent to the heavens): “… We went on, and we came to 
    something like a Tannoor (a kind of baking oven, a pit usually clay-lined 
    for baking bread).” I [the narrator] think he said, “In that oven there was 
    much noise and voices.” He said, “We looked into it and found naked men and 
    women, and a flame of fire was reaching up to them from underneath, and when 
    it reached them, they cried loudly. I asked them [the two angels], ‘Who are 
    these people?’… 

    They [the two angels] said, ‘We will tell you… those naked 
    men and women whom you saw in a structure resembling an oven, they are the 
    adulterers and the adulteresses.”

    (Narrated by al-Bukhaari in Baab Ithm al-Zunaah, no. 
    7047). 

    Please see also Question no. 11195. 

    3 – With regard to the third question, which concerns 
    marrying an adulteress when she is pregnant, it should be noted that “it is 
    not permissible to marry an adulteress until she repents, and if a man wants 
    to marry her, he must wait to make sure that she is not pregnant, which is 
    shown by her having a menstrual period, before he can marry her. If it 
    becomes apparent that she is pregnant, then it is not permissible for him to 
    marry her until she has given birth…” (Fatwa of Shaykh Muhammad ibn 
    Ibraaheem – may Allaah have mercy on him. See al-Fataawa al-Jaami’ah 
    li’l-Mar’ah al-Muslimah, 2/584) 
Based on that, marriage 
    to this woman when she is pregnant from an adulterer is an invalid marriage, 
    and the person who married her has to leave her at once, otherwise he is an 
    adulterer and the hadd punishment for adultery must be carried out on him. 

    But if he leaves her and she gives birth, and her womb 
    becomes empty, and she repents sincerely, then it will be permissible for 
    him to marry her, after he also repents. 

    4 – As for the first man – the adulterer – he must also 
    repent to Allaah, and it is not permissible for him to marry her at all, for 
    two reasons: 

    (i)because they are bother 
    adulterers, and marriage to adulterers is forbidden to believers. See 
    Question no. 11195.

    (ii)Because of her relationship 
    with another man.

    So he has to forget about her completely, and repent to 
    Allaah from his serious sin. Laa hawla wa laa quwwata illa Billaah al-‘Aliy 
    al-‘Azeem  (there is no power and no strength except with Allaah the 
    Exalted, the Almighty). 
O Allaah, guide the misguided Muslims, and 
    help us to turn back to You, O Most Merciful of those who show mercy. Praise 
    be to Allaah, the Lord of the Worlds.