Hi, Thanks for writing in. Hairy cell leukemia is a type of abnormality in lymphocytes which are white blood cells. If his counts are going down then you should consult his doctor and acknowledge them about the bruises, feeling tired and sweating. It is possible that he requires aggressive treatment for hairy cell leukemia and his general health also should be cared for. Giving him a healthy diet and adequate amount of fluids is required. Many times counts might drop during recovery also but if it is persistently reducing by large numbers then it requires to be discussed in detail keeping in mind his health condition and development of weakness and fatigue. The main features of hairy cell leukemia includes hairy cells are found in the blood and bone marrow. The number of red blood cells, white blood cells, or platelets may be lower than normal. The spleen may be larger than normal. Patients are followed up for response to treatment with chemotherapy medicines and most of them are treated. Please do not worry.