Cancellation of Thana Settlement (Gift Deed).

I am the only son age is 35. My father is at 62. My mother was expired 6 years before. Since he is not comfortable with us, He is planing for second marriage now. He genuinely requested myself and my wife to come forward and conduct the same. But I made one condition to accept that he(my father) should settle his properties to me to avoid all legal issues in future with his future companion. Then he too agreed to execute and registered a Deed of Gift (Settlement) on my name with no conditions. But now he got one companion, we came forward and have arranged him for second marriage which is going to be held next month. But after he got second companion and second marriage fixed, now he is threatening me that he is going to cancel the settlement deed since he wants to secure his new wife and her future dependent. Also he is torturing me to provide registered document copy to proceed with legal action on me. 1. Now I am in a great confusion can he revoke this settlement gift deed without my permission? 2. If he can, then what will be the loop holes? What is the justification I can defend? Note: