family property law

sir my question is recently my grandfather and grandmother died . my grandfathers nominee was my grandmother both of them died in an interval of one hour . my grandfather had two sons and three daughters out of which one son he has gifted or donated to his brother i.e. my grandfathers brother as he had no child . the donated son has all the documents in the name of his new father . my grandfather had also made an affidavit declaration that he has donated / gifted his son to his brother and henceforth the son should be called as his brothers son . after the death of my grandfather my fathers brother (my uncle ) took all the documents from the home in whihc the affidavit was also there and now we dont have a copy of that . now all the daughters and that donated son is afking for shares . i want to know whether he should get the property shares and money shares coz i have heard a child can only get the property of a single parent . as inheritance / succession , 2. will all teh married daughters of near about 20+ years of marriage are eligible for shares and by legally how to obtain the service book of my grandfather and all the revlant documents and the procedures regarding the same procurement of share / money from the bank