is Indian Succession Act 1925 applicable to Christians by inheritance

Under this law that applies to Christians, whe a spouse dies intestate, then 1/3 of his/her estate goes to the spouse and the remaining 2/3rd is divided equally among the children. So in the eyes of this law, children are to treated alike regardless of gender. But, as seen from the past, this was not practiced, and instead patriarchy was being followed. However, equality of man and woman was enshrined under the Human Rights Charter of 10th Dec, 1948 followed by Women's Rights on March 8, 1977, and yet the patriarchal malpractice continues without fear, which therefore calls for a PIL.