The details provided suggest that your father is having microcytic hypochromic anaemia with thrombocytopenia (low platelet count). Having a low Hb post CABG (bypass surgery) is normal since there is usually blood loss following the surgery. However, generally there is recovery of Hb in following 3-4 months to near normal levels. However, that does not seem to be the case with your father.
Whenever anyone has anaemia, it is either due to loss of blood / haemolysis or inadequate manufacture by the bone marrow. In your fathers' case it seems to be due to loss of blood due to haemorrhoids. This can be verified by getting a reticulocyte count done. If it is high then the marrow is functioning well and the low Hb is probably due to blood loss. However, if there is low reticulocyte count, then it is probably the marrow that is at fault. Also, low platelet count could be on account of drugs that he is receiving post CABG. What I would suggest is to get in touch with a haematologist and get a bone marrow examination done, if required. And then take it from there.