How can i get legal documents of my movable/immovable assets

We are two brothers. My mother died in 2011 and father died intestate 2015. I being the eldest and my father made me nominee of all his bank accounts, FDs & RDs. The locker was jointly held by me with my father. He has a flat in which I am residing and I am also the nominee of the same. We, two brothers have mutually come to an agreement and distributed among ourselves, on my instance to divide the cash and jewellery equally and I also want, as and when the property will be sold off, he will get 50% share. Since, I am working in a Govt Sector and by rules, I am bound to declare my movable/immovable assets, I want a legal documentation of the same. How can I do it ?