I tell thee, some of the questions on here!
This condition could range from the acutely serious and life threatening, to a chronically collapsed lung that may not re-expand….
The answer depends on the reason – a collapsed lung is not a diagnosis – it’s a sign, and could be due to (not to scare anyone) cancer, trauma, ‘popped lung’, and many others.
As he knows it’s collapsed, i’m assuming he’s seen a medical professional about it, and hasn’t just diagnosed it from bodging up an x-ray machine from some old photo film, lead plating, and a lump of radioactive goo……??
DrP