My sister was diagnosed with pneumonia 2wks ago, antibiotics given. she has had a low grade(101) steady fever for 13 days with severe cough.

Needs follow up ASAP: Complications from pneumonia may arise - and if she STILL HAS FEVER, I would be very concerned for the development of an empyema or other complication. An empyema is pus trapped against the lung and the chest wall, and is known to occur particularly with severe disease and in certain patients who may be 'weak' to begin with (diabetes, history of cancer, certain medications like steroids etc).