Share of a sikh married daughters in father's property

I am asking for advice my mother and her sister. My Mother is 50 years and her sister is 42 years of age. And the father of my mother is probably at last stage of his life now. He has not made will for his property yet. He has 8 kille agricultural land in village bhoolpur, Distric Hoshiarpur, Punjab & has 100 yard residential area in shahdra, Delhi. My Nanaji had handover 4 kille land to my mama's (uncle) as his share from his property rest he had keep for him and he sold all tjat land. But now he is very week and is in his last days of his life. And my mama also want to want that remaining land. My nanaji is not in condition to make will. Now my mama is pressurizing to my nana nani to take his favour and handover him remaining property. And one more thing is once my mama ji had took signature of my nanaji on 4 blank papers few years ago can he misuse them the property? And how can my mother and her sister can get their legal right in property or stop thier brother to sold that property? Please advice us in this metter