Injunction on property of my father

My father is neither physically abled, nor of fully sound minded. He is a patient of dementia. His age is 72Recently I have got the evidence of a gift deed where our ancestral home is being gifted to my mother by my father last year. But they have never disclosed it to me. My elder sister and her husband are the main conspirator. Now, I doubt whether they have forcefully made my father to put a signature on a willI have audio/videographic proofs that they are threatening my father.I doubt, they may sale other properties of my father as wellAs I am posted in another city due to my job, so I may not be able to track these wrongdoing everytimeMy question is,n1. Can I put an injunction on whole of my father's property?n2. Can I file a criminal case against my mother, elder sister and husband for this kind of forgery and criminal intimidation?n3. Or, what is the suitable procedure to check the wrongdoings?