Areas of increased density on a lung scan don't necessarily mean metastasis. They can be caused by any process that fills the alveoli with fluid, pus, blood, cells (including tumor cells) or other substances resulting in lobar, diffuse or multifocal ill-defined opacities. An infection can easily do that, especially since he's been having symptoms like wheezing and shortness of breath.
If it reassures you any, I had lung mets and never had any symptoms - no pain, no shortness of breath, no wheezing, nothing. So the odds are good he just has an infection and the antibiotics will take care of it. It's good you're seeing the pulmonologist next week though, just in case.
Hope this helps!
Stage IV, liver/lung mets 8/4/2010
Xelox+Avastin 8/18/10 to 10/21/11
LAR, liver resec, HAI pump 11/11
Double lung surgery + ileo reversal 2/12
Adjuvant Xeloda 3-9/12
VATS rt. lung 12/21/12 - benign granuloma!
NED 3/17/12 to 7/13/2018, CEA<1