hello thank you for trusting HCM dear which drugs he is using?? dear many causes for fluid in the stomach cavity and but you have to get analysis of fluids for cytology and protein and sugar. most common possible causes are tuberculosis of abdomen, heart failure, liver failure, severe anemia, reactive and malignancy. if it is eosinophilic means you have to start steroid and immuno modulator. if getting remission you have to maintain maintenance therapy.many immunosuppressive drugs available but consult your doctor he will advice right drug according to your problem. I think I answered to your question if you have more questions feel free to ask. take care