Can mother refuse to divide the property equally among children

A grand mother has 2 sons and a daughter. Younger son named Mr.X got married and he has 2 sons Mr.A & Mr.B . Mr.X is passed away. Now, Mr.A & Mr.B are living with this grand mother. Elder Son Mr.Y is still unmarried and resides with this grand mother. Daughter Mrs.Z is married, and she has a son and a daughter. Now, grand mother is refusing to distribute her properties equally to Mr.X, Mr.Y and Mrs.Z. She is planning to give the property only to the 2 sons of Mr.X. Please suggest, whether there is any option for Mr.Y and Mrs.Z to get their properties from their mother.