My Cousin Is Suffering From Jaundice Along With Very Low

My cousin is suffering from jaundice along with very low white blood cell count... they already tested for bone marrow cancer and came back negative but they just give him a transfusion and he is better for a few weeks until he catches a cold or something and becomes sick again... white cell count drops again and becomes jaundice again until they give him more transfusions... This is just becoming a band-aid and just a temporary fix. Any idea, I feel like all the doctors are just looking for more cancer and everything comes back the same results