Does Islamic law permit a husband to remove his 9-year-old orphaned stepdaughter, who has been living with him since she was 4 years old, from her mother and siblings to live with her grandmother, knowing that he does not provide for her, and that one of the mother's conditions for marriage was her daughter's continued presence with her? What drives him to do this is the girl's past health conditions that affected the household's routine, and his fear of that recurring, in addition to her being infected with a virus that could expose her siblings to infection despite the mother's precautions, and knowing that the mother suffers from this behavior and the child's strong attachment to her?

The jurists have stipulated that a husband is not permitted to prevent his wife from housing her child from another man with them if he knew about it at the time of marriage, or if he did not know but the child had no custodian. However, if he did not know and the child had a custodian, then the wife is not allowed to house the child except with his consent. If the husband fears harm from the child's residency, he has the right to refuse to house the child with him. In your case, since the mother stipulated that her daughter reside with her at the time of marriage, the husband must fulfill this condition unless he fears harm to his own children from the daughter residing with them. In that case, he has the right to refuse, and the custody of the daughter would transfer to the maternal grandmother.