Never-smoker's slowly resolving lung mass -- could it be lung cancer?

My husband, 67, had double pneumonia as a result of a scarlet fever infection as a child of 6.  His pulmonologist told him that as a result his lungs have been compromised and will be slower to heal than in normal folks.

Fast forward to November of this year when on Nov. 10 he came down with a dry, non-productive cough that was merely annoying.  On Nov. 20, however, he presented with a high -- 104-degree -- fever, chills, and his chest began hurting.

I had Cipro -- for recurrent sinus infections that sometimes progress rapidly to pneumonia -- and he took that for 15 days.

During the interim he had to move 25 bales of hay from one barn to another, which I recommended that he not do but which he did anyway.

He also did a lot of field brush-hogging prior to getting this infection.  It was wet this year and there was a lot of seeds, pollen, etc. swirling around in the air.

Our basement, since it was so wet in our old farmhouse (where we live only during fall hunting seasons), had filled with water as well, another possible source of infection.

Anyway, his fever improved but he continued to feel tired and fatigued so he went to a new doctor (our old one is in St. Louis; we moved 12 years ago to a lake community in mid-Missouri) who did pulmonary function tests (all good) and got a chest X-ray which showed pneumonia.

This doctor prescribed 10 days of Levaquin.

Since that time my husband has had 2 additional chest X-rays, each of which showed that the pneumonia -- or mass - was slowly decreasing in size.

Ten days ago, however, the doctor asked for a CT scan which, again, showed that the mass had decreased yet again until it was 3cm x 7cm.

The doctor has now ordered a PET scan, which has both of us out of our minds with worry.  He did this even after admitting that his 'gut feeling' was that this was a 'slowly resolving pneumonia' possibly caused by apergillus or some other fungal infection.

I am upset because I know that granulomas, sarcoids and aspergillus (aspergillosis) can all uptake the PET glucose medium at a rapid rate that can often mimic that of cancer.  If that is what happens then my husband -- and I -- will be subject to yet another week or two or three of anxiety, which cannot be good for the health, as we try to arrange the next step, which is sure to be a thoracectomy or needle biopsy or something.

So, based upon what I've written here does anyone have an idea how much of a chance there is that my husband has lung cancer?

I forgot to add that 9 months ago he had a full body scan, a full body MRI and CT scan as he prepared to undergo treatment for a Gleason 3+3 prostate cancer with proton radiation and they found no signs of metastasis anywhere in his body.  The prostate cancer wasn't aggressive and responded exceedingly well to the radiation, so much so that it is believed he is now free of that cancer.

And now this!

I've posted this twice -- the first time I didn't realize what the 'tags' did; this time I'm using tags because so far I've had no responses.  Sorry.