My deceased father take loan 50 lacks on the basis of land worth 1 crore

Hi, My name is Vilash Thapa. I live in Diphu town, dist-karbi anglong, Assam. My father was deceased last month and he made a loan basis agreement of 50 lacks rupees. If he unable to pay within 6 months of time period then he will hand over his 2 katha land worth 1 crore to the lender without any claim or no objection by him or his generation in future. (6 months is over) the lender has our land documents. My mother or any other family members didn't knew about this earlier. The lender came and told this after my father death. So my question is Can we return the money to the lender and take our land back?