For years during and after my divorce I would have days-long episode of runny sinuses. Eventually I learned it wasn't a cold because only one sinus was draining, though sometimes as one dried up the other side would start.
I consulted a practitioner of EMDR or body balancing. A lot is rooted from early childhood issues, but recently triggered. For men, left side (most common for me) meant emotional problems from others, right side was my own emotional issues.
That's crazy, I've had the same exact thing going on with my left sinus. It started about 4-5 years ago while still married, and has been slowly getting better over the last year. I felt a constant light stinging in that sinus, and lots of discharge. Almost gone now. It's refreshing to read an explanation for it, I assumed it was related to stress somehow.
JNChell, sorry I didn't answer your question as I was away from the forum for awhile. I live in the U.S. in a large metro area that leans left. I hope things get better for you and your son, just take it one day at a time.