WILL note payment to pay daughter

Our family comprise my mother-in-law,my husband and my husband's two sisters who has be married and living with their husbands abroad. Me and my husband also living abroad.All we r in different countries now and rarely had a chance to meet each other. My husbands father wrote the will when he was ailing with age problems, stating that my husband is the sole owner of the land and house after the death of father-in-law. mother-in-law has all the rights to live in that land and house untill her death. Also our sister-in-laws had to be paid a lump-sum amount of money within two year off death of father-in-law otherwise sister-in-laws can claim for that amt on property legally. After our fathers passing away one of our sister have given the written statment legally. The second sis is been paid twice (thru mother(1) and by us uae exchange(1) ). we been assured verbally that she will clear the legal when she visits kerala but the promise is been broken as her husband is greedy and demanding. now its been 5 year after our fathers death still we have to request her to complete the formality of will. We wish to build a new house in that land and worried about the bank formalities due to this pending paper work. As far as we find it difficult to reach an amicable solution and sister is not keeping her words what can be the legal solution. We had the documents of paying money(thru mum,and thru uae exchange)