Me and my mother name on property card of my deceased father -zubin

I have some land in Mahalaxmi –Mumbai .My father died in 1987 where there was a property card with his remaining 06 siblings names on it(including my father ) ,I was told that to add my mother & my name on property card It will cost us Rs80,000 .Which after checking with my “various sources “ did not find true and was told only furnish my father death certificate .Please can you look into and revert to me at the soonest My father name was also on the property card and I need to know the answers as It will help understand my families intentions Seconldy When the property is on all 06 names (04 brothers & 2 sisters).Can one sibling go ahead and Furnish unauthorized NOC for various transactions without the permission of the other 05 siblings .Please answer these questions.