What is the position of the Islamic religion on the extreme harshness of the grandmother and maternal uncles, which reaches the point of humiliation, oppression, and severe beating, towards their grandson or granddaughter who live in the home of their divorced mother's family?

The mercy shown by grandparents and maternal uncles towards their grandchildren and nephews/nieces is both an innate disposition and a religious duty. The absence of such mercy indicates hardness of heart and goes against both innate disposition and religious law. Grandchildren and nephews/nieces must not reciprocate this harshness in kind. Rather, they should treat them kindly and be patient with their harshness, so that they may receive Allah's help and victory. For the one who maintains ties is not he who reciprocates, but he who maintains ties with those who cut him off.