A similar question has already been asked by you at the link: Property issue – right of grandson when property transferred to son due to registered will. Please do not ask repeated questions separately. If there is a supplementary question, ask in the same question link.
Anyway, on the basis of the facts mentioned by you, in my opinion, your son cannot demand a share if the property was validly transferred to you under a registered will.
However, please check on what grounds your son has challenged it and sought a share in the property. He might either be asking on the ground that it was HUF joint property (not being self-earned property of your father, but an ancestral property) or he might be suspecting a fraud in the will or the transfer of property to you, or may be something else.
It would be advisable for you to show all relevant documents to some local lawyer and get proper guidance. In particular, you should show to the local lawyer, the grounds on which your son has filed a case because I am suspecting that he would have taken some grounds which are not consistent with the facts mentioned by you.
Dr. Ashok Dhamija is a New Delhi based Supreme Court Advocate and author of law books. Read more about him by clicking here. List of his Forum Replies. List of his other articles. List of his Quora Answers. List of his YouTube Videos.