Misuse of POA of missing person 

My uncle did forgery fraud with inventory partition deed in 2000 for Goa properties without our involvement,claimed ownership thr court order..He did unregistered POA to his son in 2004 at Mumbai without witness.He is presumably dead by 2012 as per law.  we filed civil suit in 2012 when we realised presently in court..He went missing from Mumbai in 2005, fir filed.His son informed court recently about his missing status...His son executed sale deeds of suit properties..what is the option available for me..Pl advice..Thx..