Is barley good for treating anemia?

No, why would it be? Anemia is lower concentration of RBCs in blood, in turn a result of RBC production (bone marrow) longevity of RBCs combined with rates of RBC loss (bleeding; internal & external). To reproduce, marrow needs DNA (B-12&Folate), fat for membranes, hemoglobin (huge protein+heme ring+Fe+2 atom). Barely is a grain, high carb, moderate protein, low fat, little value to bone marrow for RBC production.