According to recent SC judgment, a precedent has been created in favour of law-abusing NRI spouses.
Matrimonial 'offenders' can't be extradited: SC
It is known fact that India is not signatory to Hague convention which means child custody orders in foreign courts are not of significance in India. This means that an Indian parent who 'abducts' own child in foreign country and brings to India can't be touched by laws of adopted country. Even if she/he has foreign court orders against her/him the orders cannot be enforced or respected while in India.
So all NRIs who have abusive spouse have to be very careful if they have any children. If the spouse brings children to India, she can file for custody of children in India even if the foreign courts had granted custody to other parent.
And usually custody is granted to mothers by courts, for children less than 5 years it is automatically with mother (as per HMGA 1956). The case drags for some time and once the child gets settled with a parent, courts will not interfere with status quo.