Property inherited by my father from my grand father

Hi Sir, My grandfather's property was divided among his 9 children after his death and my father has got his piece of land as part of partition. The entire property was bought by my grandfather during his time and not inherited from his ancestors. The land was partitioned and the document/stamp paper has all details about which survey number belongs to which son and this is not registered separately by each son . I am the only son(my age is 36) for my father(Age 75) and due to spendthrift nature, my father is trying to sell it . My questions are below. 1. Can he sell it without my consent? 2. If he tries to sell it, Can I stop it by giving a request with some authorities? I have heard about stop memos to stop future transactions in a disputed land. 3. Since there are arguments and difference of opinion in the house, and my father being a very adamant person, Can he write a will to give away the property to someone? Is the will valid? Please let me know your opinion. Thanks.