You would expect a mixed infection in an aspiration pneumonia from mouth flora. The mediastinal nodes were most likely from acute lymph adenitis and his spleen was acute splenic hyperplasia. The urinary changes of blood and neutrophils indicate the possibility of septicemia with microabscesses and pyelonephritis. The abdomen is most likely adynamic ileus 2nd to the pyelonephritis. Lung with foamy or frothy eosinophilic material within some alveolar spaces and alveolar septa thickened by mononuclear inflammatory cells and edema.
Some macrophages are in the alveolar spaces.
The frothy eosinophilic intra-alveolar material is highly suggestive of pneumocystis. The marked prolonged immunosuppression to try to control his symptoms from regional enteritis.