I'm so very sorry to hear that your little one is so sick. That's awful.
Has your doctor prescribed any breathing medications, or bronchio-dilators such as Albuterol? What about Pulmicort, an inhaled steroid to clear up any inflammation in his airway?
Three of my children have inhaled medications for wheezing, and other Asthma symptoms. I'm not saying your son has Asthma, but he could have something similar, such as Reactive Airway Disease.
I would encourage you to speak to your doctor about this. Hang in there,
Karri