Sister's claim over father's property

My father is a retired elementary school teacher from remote village in T.V Malai dt. He got retired in 1998. I'm the only son got married in 1999 at an early age of 24 due to my father's health problems and 02 elder sisters (39 and 41 yrs old) got married in 1992 and 1995. Second elder sister has filed a case on my father to give shares on all the sold and holding properties. But my father is not willing to give share as few were already sold to meet family expenses and sister's marriage expenses/loans. Details of sold and holding property 1) 3.0 acres of agricultural land sold for Rs- 6000/ only in 1983 to meet some family expenses. (Land given by my grandfather as a share to my father) 2)0.60 acre of agricultural land sold in 1988 for Rs-3000/ only. (Land given by my grandfather as a share to my father) 3)1.0 acre of agricultural land sold in 1996 to settle some hand-loans borrowed for 2nd sister's marriage expenses. (This land was gifted to my mother by my mother's father) 4)2.5 acres of agricultural land registered in my father's name- still holding (1.5 acre of land given by my grandfather as a share to my father and 1.0 acre land was bought by my father) 5)One house in nearby town, where my parents are currently residing. (This piece of ground was bought by my father with his retirement money and house was built by me taking personal loans/handloans in 2006-08. At that time, can't take home loan in that town and city banks don't give loan to build home in other towns) Now the second sister has issued a legal notice seeking share in all the already sold and presently holding properties. Myself and 1st elder sister are in support to my father. Pls tell me, whether she can legally eligible to seek share on the above 5 listed properties Need your kind guidance and advice. Awaiting your reply, Thanks in advance..!!!