Unregistered

One father and three sons mutually made unregistered partition of ancestral property...the father got this property from father as ancestral property...... The three sons are the property ....this unregistered property ifs.partitiined 39 years back on unregistered papers ,without stamp and notary sign............ The three sons registered their some properties respectively and and their respective agricultural land not registered and agricultural land details were uploaded on govt site and obtained passbooks....... The main question is ,what is the nature of sons registered property and unregistered agricultural land ..... Can the property be called as self acquired as it is in hands of sons and they are enjoying it for.the last 39 years .....??? .................................................. .. The mother of three sons is senior citizen..she has got property....after her time ,shall her property go to sons or grand children??? Shall the grand.chidren has legal rights on grandmother property?????. .........................................................