Ancestral property document in bank locker for transparency

we have ancestral property with undivided & unpartitioned . my father inherited from his father . my father had 3 sons and 1 daughter. im being younger son of all. one of my brother died and next brother is keeping ancestral property document with him. when i asked property document for taking xerox copy for my use, he refused to give . Also he is in talks to sell his share to our undivided ancestral property . i was in a opinion to keep property document in bank locker in joint account making the locker movement transparent . but he refused to do so. in such scenario how i can make him to deposit ancestral property in bank locker so as there will be transparency among all 4 members of our family