regarding family settlement

dear Sir, My grand father was revenue patwari,he had 2 sons and six daughters,my grandfather purchased a plot 10 marla in 1963 in the name of our grandmother. In 1975 my grandmother gave 8 marla land to my uncle and my dad in oral family settlement. In 1984 she further sold 2 marla land to my dad and my uncle one marla she left with no land. In 1985 a memorandum of family settlement was reduced in to writing in this regard in stamp papers with the witness of my grandfather and one family friend.the entries were changed in municipal record.ts1 were made.the entries were not changed in revenue record. My dad and my uncles made there houses and shops separate and two shops each were rented out. In 1992 mu grandfather died.In 1998 my grandmother was living with my uncle who got a registered will of total 10 marla from our grandmother. Our grandmother had given already 8 marla in family settlement and 2 marla in registry.uncle filed a suit of declaration and possession of property against my father.whether our family settlement valid. It is not registered but memorandum reduced in to writing.