Rulings on
    upholding the ties of kinship for females
Question

                my sister who has shahada is married
      to a man who is not, at the time she didn;t know that he is haram for her. My husband will
      not allow me to visit her home because he is not muslim, it this allowed? I would just
      visit her home when he is not there
Praise be to Allah.There follow some details about the issue of women
    upholding their ties of kinship, and what they should do with husbands who prevent them
    from doing so.
Upholding the ties of kinship is obligatory even for females, who must
    uphold them as much as they can. Therefore it is not permissible for a man to prevent his
    wife or daughter from upholding her ties of kinship, and if he stops her from visiting
    them, but he lets her convey greetings to them, whether by letter or through a third
    person, or send them gifts, then she should do that. It is sufficient even if she only
    sends greetings without a gift, but if she sends her greetings with a gift, that is
    better. If he stops her from sending a gift but allows her to send greetings, then she
    should send greetings. If he allows her to send a gift but stops her from sending
    greetings, then she should send a gift. If he allows her to go and see them, then she
    should go. If he stops her from doing anything that comes under the heading of upholding
    ties of kinship, then there is no obedience to any created being if it involves
    disobedience to the Creator. In this case she should maintain her family ties in the way
    that is least objectionable to her husband or father, whether it is sending gifts or
    conveying greetings, and she can conceal that if she is fearful. If her relatives are
    faced with some hardship, she should help them with what they need, even if he says not
    to. She should uphold her family ties by offering condolences in the case of bereavement
    or loss, and condolence means advising patience. She should also congratulate them on
    joyful occasions, and congratulating them means praying that they will enjoy to the full
    whatever has brought them joy, and that it will not be spoilt for them. Such joyful events
    include the return of a traveller, a wedding, etc. She should not adorn herself or display
    her adornment in front of those to whom she should not show herself, such as cousins (sons
    of maternal uncles or paternal uncles), and she should convey her greetings to them from
    behind a barrier and without making her voice soft, but this is only in cases where there
    is no fear of fitnah, otherwise she may convey greetings through a third party. She does
    not have to attend funerals.
It is not permissible for the husband to stop his wife from upholding the
    ties of kinship even if it involves her going out, but she should not go out except with
    his permission. The same applies to fathers. The wife should treat her husband gently so
    that she will still be able to fulfil her shar’i duty of upholding the ties of
    kinship. We ask Allaah to put all our affairs in order.