Low level of blood count. To down?

Ma father is diagnosed with phemonia almost 1 month back. Now he recovered with phemonia but now his hemoglobin is sometimes going down and after 2days its going up like low is 6.5 and high is 8. Also he has an enlarge spleen and low level of blood pressure. He is an high blood pressure patient but because of his low level of pressure doctors stopped his medication of pressure. Now he is having the pressure sometimes 110/70 or sometimes 120/70.he is also having huge back pain. Sometimes pain in chest but the ecg looks okay. Doctors want to do bone marrow test nd tommorow the bone marrow test will be done. He is having low level of white blood cell and high level of uric acid. I am tensed because m not able to understand why the hemoglobin if getting down so frequently. Is the reason is pnemonia? I dnt think he is having that infection now then what cause his hemoglobin to down?