Cough and breathing problem. Clearly?

My grandmother having serious problem of coughing with pain. She has also low oxygen levels of 91 , in c. T scan doctors seen multiple discrete nodules are seen scattered throughout the lung parenchyma bilaterally with largest measuring 8mm in size. Smooth septal thickning is also seen in both the lungs mild bilateral pleural effusions are seen, right more than left. Mild pericardial effusions is also seen. Trachea and main bronchi are normal. Major vessels in media stinum are normal. No evidence of bony erosion or paraspinal mass lesion seen. No evidence of honeycomb shadow, subpleural bands or interstitial thickning seen in lungs. The upper abdominal structures are normal. No enlarged hilar or mediastinal lymph nodes are seen. The axillary and supraclavicular areas are normal.and in her cough test she has tested negative for mallignant cells and TB bacteria.So What should be done , which specialist do I consult what is her exact issue and why doctor are not saying anything clearly ?