I'm sorry to hear the news Anna. Hopefully he's taking an antibiotic now and will kick that infection to the curb soonest.
Since my immunoglobulins (IgA, IgG....) are basically zero, I can count on an infection each time I get a cold or some kind of sinus issue. Because of that, I start levaquin as soon as symptoms set in....works every time
Wishing you and Dad the best
Doug