Suggest Treatment For Chronic Anemia

Hello- my mom has chronic anemia x 3 years with no known cause yet. She is 64. Last hgb was 8.6. And hct 28. She feels awful. Her hgb was 9.6 about 1 week ago. Within the past week the doc sent her to hospital bc of + d dimer and shortness of breath. Found fluid around her heart/lungs and found lv diastolic dysfunction via cath (clean coronary though). She has hx of dm but no htn so they arent quite sure why she has heart failure. They started her on coreg 3.125, lipitor 10, imdur 30, Losartan 30, and furosemide 40. We had to temporarily hold the arb/statin due to dizziness/severe nausea. She was dizzy without low pressure. She hangs out 110-130/50s. My concern now is she can hardly walk to bathroom without complete exhaustion. Is it reasonable to ask the heme doc about prbc or iv iron?I know we need to identify the cause but in the interim she feels awful. Plans for ct scan abd/pelvis in future as chest ct was clear