Rights on Ancestral Property

Property owened by my Grand Father & his two younger Brothers had been partitioned / separated before the settlement authority in 1963 and Separate “Patta/record” had been issued to each . Again due to disagree with the separation they had mutually agreed to exchange some plots from their “Khatas / records” among them and filed another partition suit accordingly in 1983 . In the mean time my Grand Father had died in 1984. The re-partition had been dropped since then. The legal hires of above three shares sold their occupied/aquired Plots as mutually agreed earlier. My grand father’s Sister had died in 1978. But the nephew of my grand father (Son of their Sister) now claimed in 2017 his mother’s share saying the the partition in not valid . Kindly advice that has he got the right to claim a share of his mother from us when his three uncles (Brothers of his mother) are dead and the re-partition of the property is pending since 1983 due to dispute among the legal hires of the property.