Regarding Natham Land dividend between brothers

How to divide a grand father Natham land 4 between brothers. What are the procedure to do it official. Hi All 1) In TamilNadu, Natham land and document in grand father name. Grand Father died 20 years back. 2) 4 brothers. 1 died long time back. 3) In front of village heads long time back, land divided and written in white sheet(No official partition document). 4) Part of house given to last brother. he paid some amount that time mention in that white sheet. 5) As last brother out side village for job, another brother lived there till 3 years back. 6) Now he moved to new home build nearby in same family land.(there is no official partition documents yet) 7) Another brother also build new home in another part of the same family land(there is no official partition documents yet). 8) Now the old home which is in state of fall and he request the last brother to destroy the house. 9) Also he build the house in last brother land(10%). As the last son not lived there after the partition(in White paper), Also another brother who lived in that house while going out from that house, he damaged because of this the house in a situation of fall. But people asking last brother to destroy the house. But he never lived there and no official partition document. 1) If the wall fall itself, will any thing affect the last brother? 2) How to remove the wall which in is in the last brother land? 3) Should the last brother destroy the house? Thanks