My grand father[A] purchase a plot size÷500 sqrd along with his own brother[B] in yr 1980 and his brother made an unregistered release deed in year 1983 in favour of my grand father and release his 50%share and in 2003 it was validate in the presence of [B] and in 2007 my grand father gifted the entire property of 500sqyd to his 4sons and [B] is still alive and never raised any questions in 2008 my grand father died leaving his legal heirs behind after the completion of 3yrs of registered gift deed in the 2010 the person [B] who was his brother also died in year 2012 all 4 legal heirs did partation and in 2013 they obtain NOC from collector for the purpose of construction and then suddenly the legal heirs of [B] filed a case that 250sqrd belongs to them with the aim of evil intension so my question here is while person [B] was alive he never challange or raised any questions even when the registered gift deed was executed he never objected nor file any complain and after completing 3yrs of time he died and on that basis we made a partation deed now legal heirs of person [B]files a case by collecting link document I.e release deed that his father never executed any release deed on the name of person [A] and the document is forge and even they don't wanna challange the document or send it to forensic test and nor they believe that registered gift deed is bar by limitation of 3yrsof reg document and they father person [B] never challange gift deed till his death so I need a guidance on this issue as
