Status Of Bank Locker

I have a Bank Locker held jointly with my father , and could be operated by either of us. My Father expired 2 years ago. He made a registered Will 13 years ago in my favour. After his death my brother told us that our father had Executed another registered will regarding the said Locker in his favour 4 month before his death. My father was a neuro patient since 2 years before his death. On examination of this Will regarding Locker we found following Lacunae -- 1 - It has only Thumb impression and no signature. 2- It has no reference of his earlier Will nor it cancells it. What is My Status in the Locker now.