Partition suit

My husband's grandfather made a partition deed in favour of my husband and his sisters, Since my husband and sister were minor at the time of partition , so they showed my husband mother as guardian for the properties,as a Guardian my husband's mother transferred the properties in her name. Both my husband's elder sister and younger sister wrote and registered relinquishment deed to my husband and his mother. Now my husband's mother make a sale agreement of our agricultural land to another person without my husband's signature and we came to know the agreement afterwards and put the partition suit against my husband mother and took a temporary injection order for the properties. After took a temporary injection order for the properties that another person put a OS againest my husbands mother and they internally compromised in loka adalat and make a decree without my husband notice. then we put IA in their execution petition as a objector. Now recently my husband expired and i have a two samll daughters , my question is that sale agreement is valid or null? Will my husband mother have a rights to do so agreements alone without my husband signature Can i continue the case with full rights? Please help with suggestions How much share can we get in the property, hence my brother sisters writes the relinquishment deed