Family estate dispute

My father passed away in 1998 & my mother a year later leaving behind their assets to be shared between my elder brother who passed away in 2015 survived by his wife and unmarried son (25), my married sister in UK & myself married in India. We reached a family settlement which was notorised and registered but before we could divide the assets my brother passed away and now his wife is sitting on all documents, shares, etc and is not willing to act to make a probate or settle the issue as agreed upon, what is my legal recourse. I am now the Karta of the HUF but have no property documents nor the share certificates in my possession.