Father - in- law's property division among brothers and sisters

Hello, My late husband has three brothers and two sisters. We are Muslims. The land we reside on is in my late father-in-law's name. My sister-in-laws never married and they live with us along with my elder brother-in-law who is a divorcee. The other two brothers also reside on the property with their families in separate houses. One of the brother-in-laws took the property division issue to jamath wherein the jamath asked us to divide the land into 5 portions, with brothers getting one portion each and sisters getting 1/2 portion. Now the same troublesome brother was not happy with the result since the land was divided horizontally and age wise he got the third portion away from the road. He has now sent us a legal notice asking for his land share. 1) What is the fastest hassle-free course of action to get our share? 2) How much of the Jamath's decision is valid? 3) Can we approach a buyer for our share of land without a partition deed? 4) Is it possible for the remaining 5 people to sell their lands without the consent of the troublesome brother? 5) How much rights do I have on my late husband's share?