Can my grand father make the settlement document void

I am a Hindu. My grand father has registered a settlement document for our house expecting only love from us in return. It is registered such that my grand father will use the property lifetime without the right to sell or donate. After he expires my grand mother can use it without right to sell or donate. Then it comes to my Father and mother who can use without right to sell or donate from whom me and my brother will inherit the property with full rights. My grand father wants to make the settlement document void. Does he have the right to do so legally?