Lung Nodules

My father is a 59 year old former smoker - he quit 2 months ago. He has COPD and a small nodule was discovered on his lung. His GP thinks it may be a granuloma but he sent him for a CT Scan.
His CT Scan came back inconclusive - due to the COPD, he has swollen lungs and the CT Scan was not useful.
He is sending him for a PET scan.
Does this mean that the nodule is cancerous and the PET scan is staging the cancer...or does it mean that the pET scan will determine if the nodule is cancerous.
I am confused and worried.
Thanks