I want to to buy my grandfather's property. My is only child of my grandfather. My grandmother is

I want to to buy my grandfather's property. My is only child of my grandfather. My grandmother is alive. For financial problem and other debt they wants to sell the property. Can I buy this property. It is legal or illegal. We are two brothers. He is opposing. My religion is hindu. My father and grandmother both are ready to sell the property to me. Please guide me.