(Fatwa: 641/641=M -1429
The mother has the right to nurture a child up to seven of his age provided the upbringing right of the mother has not been terminated and the father is responsible for the fostering expenditures. The father can keep the child with him when he is seven years old and father should make good arrangements for the child to get educated and nurtured. When the children are mature, it is up to them whether to live with the father or the mother, they have options to choose.
Allah (Subhana Wa Ta’ala) knows Best
Darul Uloom Deoband