2. Help your father find documents such as title deeds (usually the village committee will have relevant information).
3, can't find documents to find witnesses, request the village committee to participate in the coordination.
4, coordination doesn't work, learn to use legal means to safeguard their rights and interests.
PS: trick: you can't make mistakes. You can seduce or provoke your neighbors to make mistakes, so being reasonable becomes unreasonable. . . (Not recommended)