jointly purchased

Sir, my father and mother jointly purchased a plot in 1978. but the plot is in the name of my deceased father. My mother gave 50% amount to my father for the purchase of plot. My mother gave 50% amount after selling her Gold jewelry. my Mamu is witness of the. Our father also told me and my elder brother in his life that this plot is purchased by me and your mother jointly.
Now, can our mother claim 50% share in the property of deceased father.