Land captured by neighbour

We belong to ST community we have land near entrence of village . Where we all live and we have all documents of land. But on one side of land it is captured by Muslim family. Their father used to work on our land , my great grandfather had made a hut for them . They were husband and wife and they were from bihar (migrated) . father while working there bought new land and settled his family there but his youngest son ( as old as my grandmother) wanted the piece of land as it is near road (high value property). Fought with my grandfather and stayed there and we are fighting case from 15 yrs . I thing our lawyer is ripping off my grandmother ( as they are not educated). Meanwhile they made some documents claiming my great grandfather donate that piece of land to them. Till now hut is intact, they are not able to build pakka house. Whats is solution for this . We can't sell our property to non-st and here someone wants to capture our land due to high property value. As we are largest and oldest family in village that has land intact. Other villages have jealousy towards us and don't support us in any dispute. They all had more or equal land as compared to us but they got greeedy and sold thier lands.