C.R.
I would highly recommend checking for food allergies AND intolerances. I suffered with sinues headaches, had surgeries, and took a myriad of drugs for 25 years before a doctor diagnosed my gluten and dairy intolerance. By then excema and severe stomach problems had been added to the early headache symptoms. Avoiding these foods changed my life and got me off sinus medication. Your son might have diffferent allergies, so I'd encourage you to see someone who specializes in it. The Jaffe Food Allergy Institute at Mt Sinai might be helpful.