Encroachment combining Revenue land and left over land after sale.

Dear Kaanoon Members, 1) My father purchased a property from one person(say A) in 1985. 2) Person A was holding 16000 Sq.ft. From which 2400 Sq.ft sold to my father with a sale deed mentioning the boundaries as West is Main road, south is 20 ft road, north and east is sold to different people. 3) My father owned the land in 1985 and built house in 1992. Since 1992 till date we are living here. 4) A's son is claiming that in the west side of my father's property there is a land belongs to him and left unregistered with in the 16000Sq.feet. That unregistered land is now registered by A's son with a settlement deed to his daughter measuring 1000Sq.ft(20L*40B). 5) However as per measurement the road is 60 feet wide. Meaning between my father's property and the road there may be 2 or 3 feet of left over land and not 1000Sq.feet. 5) Can you tell me does he have any right over the 2 or 3 feet of land and that by creating such sale deed for 1000Sq.feet can he own the land of 3feet left over land(i.e 3L*40B) and 20 feet land belonging to road(20L*40B). 6) He is asking us to use south side of the road, but our construction is facing west as frontage. 7) The registration is done in 2011 and I realized in 2017. 8) Can I file a civil suit on this matter or it has crossed its limitation period.