Salaam, If a wife desert her husband, running away from her matrimonial house and going to another country along with the child and there file for divorce after two months. She still has any rights on her child even the father deny to give divorce and the court award her divorce.
When the divorcee took the child to another country, she has right to nourish the son till the age of 7 years. In case, the child is a girl, she can keep her with her till she is grown up. Then only, the father can have them in his custody.
Allah (Subhana Wa Ta’ala) knows Best
Darul Uloom Deoband