Girl Child education

Hello, My sister is married in a dense village she have two daughters the family is not so supportive at all for their education even his husband is not educated. We tried to educate her elder daughter and asked them to send at our city where we live but they denied that they will educate her in village only. After 2-3 years we saw no initiative taken by them we somehow convinced them and managed to get her younger daughter and enrolled in a city school but my sister got harassed on this issue continuously they keep on bainwashing her daughter to come back to Village.This year her daughter passed class 3rd and we sent her for Holi and they brainwashed her now she is refusing to come back . That family is not at all supportive for education, her elder sister is now 13 years of age enrolled in nearby government school she hardly able to write her name because they don't send her school properly ,she was kept busy in household works and all. Please tell me if there is any solution for this.. Thank you