My husband has had chf numerous times as recently as Christmas day, 2016. Had to be flown to the Mayo clinic in Jacksonville. Confirmed pneumonia. He also has COPD along with lymphoma, non-hodgkin b cell. Has had 4 treatments of Rituxan. Question. How long can this pneumonia last? He has had it already for 3 weeks. He is 64 yrs old. Extremely weak. No energy.