False Forgery case was registered on my father in police station

I m in great worry while writing this question. Backstory: my fathers grand father had two sons the younger one is my Dad's Dad and the elder one has 1 son and 3 sisters. My father has a younger brother so total 3 heirs(Sons/Males) for ancestral property How it stared : Now one of the daughters of my Father's Paternal Uncle (the Elder one, deceased long back) after knowing the New Rule of Supreme court rule to give equal share to daughters and sons which she Read in 2020 and after that she started all digging all Old Land documents of Grandfathers Ancestral Property and torturing US There are no Lands now on my fathers name which were all sold off. there are only few acres left and all are in the name of My Fathers own brother who dint sell it. My father explained every thing to her about all the lands as far he remembered to Him cause it was in 80's 90's and recently was 2006 and why he had to sell his share For Eg for sisters marriages maintenance etc. and it was cheap in those Times and my father had none left for US. Current Situation: Coming to todays time where last year She sends us a notice on all the lands with survey numbers etc that all this was unequal sharing happened etc., notice include all the Data of lands and persons who Sold and re sold from 1980s she want that to be shared between all the Grand sons and grand daughters of my Fathers Grand father. and later had cool down on that for a while and wants the remaining land which was on My fathers Own brother to be shared to which he disagreed. i need advise or help on this below matter : Now the real issue is in one of Land which was Sold(Transferred) to a 3rd party in year 2004-2006 (don't have exact data with me) where my father and his own brother signed and My fathers Cousin brother (Fathers Paternal Uncles son) should also sign it to sell the property to the 3rd party who are in Kabja(Doing agriculture) of that land for many years. now in the year 2004-2006 they wanted that the land should be transferred to their name by giving some nominal amount They asked my dad and my uncle and to which my father signed first and my Fathers own brother did it when the 3rd party forced him to sign. My father cousin brother is saying he Doesn't remember signing it to the 3rd party and he said this to His sister and this sister now gave a police complaint on Forging the signature of His brother at that time 2004-2006 , this news comes as a shocker to my Dad as he never went to a police station before this He went there and spoke with SI and he said because its a Forgery Complaint he had to call otherwise this is a Family/civil/Land Dispute only. Now yesterday my Dad got a call from an Unidentified lawyer demanding 1 Lakh rs for anticipatory bail etc and cut the call this is the back story