Property and heirs issue

Iam Diviya P , my father passed away 5 years back , my mother was his second wife , my dad's 1st wife eloped with a man after 7 yrs of their marriage and took her 2 daughter's and left the older daughter with my father (3 of the girls are the legal heirs of my grandfather's property) . The problem is my father has many debts and now my mother has to pay atlesat an interest of 80000 per month . My father owned a grocery store which my mom is running now and paying the interest only moreover she has to borrow for my higher studies now. She couldn't manage . Now my father's 1st wife and her 3 daughters are not letting my mom to sell any part of the property to pay back the debt taken by my him . They are claiming that my mom isn't a legal wife . Even after filing a case they aren't responding , my mom is tired of paying interest and borrowing more for the same. Iam just 19 and for my further studies we need money and de to the pandemic courts are closed and we are getting at the thresholds of borrowers plz help us with this . If there is any way let me know email [deleted]