Precaution to sell ancestral home

Facts 1-My father is very careless and very self centered person, during his entire life, he tortured my mom and us and did not earn single coin. we have ancestral house, now my main worry is that my father can sell this ancestral house, however at present he is totally agreed to make registry on my name-alone son or my mom name. No dispute, no problem 2-My Main question is as he careless and easily misguided by anyone to sell our this ancestral house, so how can I make a precaution that he will not be able to do so, at present, No dispute, no problem but I want to do precautionary action to reduce risk 3-As I belongs to lower middle class family so I also cant bear 2.5 % or 1 % stamp duty for making registry meaninglessly but as the risk is very huge, what is the cheapest way to only get a solution that he will not be able to sell house. My mom and me, all are we one side. 4-Gift deed or will or any other cheapest way.....please tell me the cheapest/economical way to get precaution. 4- The house is situated in village of rajasthan and approx market value is 30 Lakh, The house is belong to my grandfather or his father, This house is not in my father's name