Property related

My aunty & uncle (i.e. my father's sister & my father's brother) both have purchased a flat about 20 years back. My aunt was staying with me as she was unmarried. I use to bear all expenses on account of her, though it is personal/hospitalisation. My uncle was staying in the flat which they both owned. My aunty never made any will saying that on her death I will inherit the flat as even uncle had no dependent's though he was married & his wife expired long back My aunty expired in 2013 whereas my uncle about 4 months back After aunts death our uncle spoilt relations with us for petty reasons Out of rage he has made a registered will & nominated a person who says that he is uncles best friend My question is how can uncle make a will of entire flat when the society records has name of my uncle & aunty Secondly what we came to know is that uncle had already sold this flat to 2 person and have taken some small token money If he had intention to sell the flat then what is the need of will? The case is very tricky I know but in absence of will from my aunts side how can i claim get the flat transferred on my name