Is living with only one lung possible. lady diagnosed with radiation fibrosis after cancer therapy. is radiation fibrosis of lung progressive?

Sure: Some degree of radiation fibrosis is to be expected. Different people get less or more. It's usually little or no trouble. People actually have lungs removed for lung cancer, and do okay afterwards. I hope she got a good result from her cancer treatment, and that if she smokes now, she will stop. Best wishes.

Let me address your?: Yes, one healthy Lung is enough to live a near normal life. Radiation fibrosis can damage the lung to varying degrees but it very likely will have some remaining function . Radiation fibrosis can be progressive but only in the affected lung. I think she will do well in the long run. A course of steroids may be useful. Consult the Radiation oncologist who did the treatment with Radiotherapy.