Do I reserve the right to ask for the copy of will?

My father's elder brother has no children. My great mother has got in her 2 sisters along with son of one of the sisters to their place and living together since about 22 years. Since it was a self acquired property (my great father's) I never intervened as it was my great mother's personal decision to get two of her sisters and son to her place. One of the sister colluded with son of the other sister and have been drugging my great mother and have made my great mother's health miserable. They resorted to forgery and tried to grab the land and gold. My great mother has come to know of this and blames only one of the sister for this . Now they want to sell off their land with house at one place and have already purchased an apartment at another location. I have come to know that a will has been created and that the son of one of the sister is the beneficiary(the one who has colluded with his aunt). My great mom is not able to speak properly now, that is how these people have made her. Can I, as a legal heir, being the paternal son, demand that the will, supposedly written by my great mother be shown to me. If YES then how and are there any chances of me getting the property because these people (my great mother's sisters and son) have already embezzled lakhs of rupees!!! Please advise