My Wife 45 Years A Never Smoker Was Diagnosed With

My wife 45 years a never smoker was diagnosed with adenocarcinoma of left lung, and pnemonectomy done about 1.5 years back. Last month due to breathlessness she was admitted to the hospital on a diagnosis of pneumonia. A week later with no change in symptoms, a echocardiogram revealed fluid around the heart. This was drained about 570 ml of it. The fluid was tested for any cancer cells and none was found. She was discharged to rest at home. But even after ten days now she is still suffering from severe breathlessness, cough with some spit like sputum. Her cardiologist says her heart is OK. Her pulmonoligist says her right is slowly recovering from infection. But her symptoms are not alleviated. Please suggest. Currently she is taking nebulizers three times a day.