Mother being evicted - Property Law - Florida?

My mother has lived on the "family farm" for over 20 years. Her mother and father ped away and she continued living there, the uncle (owner) gave her a piece of paper stating she could live there for the rest of her life. But nothing legal. He is still alive and i think has signed over the land to his heirs now they are evicting her. Does she have any rights? The only thing that they have asked is for her to pay the taxes (garbage and rescue) each year on the 1 acre of property where her home is. Is there a law that might protect her?