Sorry to hear about your son’s struggles. It sounds like you’re doing all the right things. For kids with chronic rhinitis and chronic cough, I am suspicious of reflux (GER/GERD) as a contributing factor. Take a look at the articles on this site for that topic. Regarding the precise amount of Manuka honey to use, it ends up being about a tablespoon for an 8-oz bottle of saline. Manuka honey may help reduce inflammation, studies have found that Manuka contains both a strong anti-microbial, and strong anti-inflammatory agents … worth a try.
Please let us know how it goes, and thanks for visiting.
Simple non-pharmacological and avoidance measures do help. For example, a simple saline (salt water) nasal douche or lavage is effective. Saline and sea water nose sprays (Sterimar) help flush pollen grains off the nasal mucosal and improve nasal patency. While a little Vaseline applied to the lower nostrils on cotton bud is both soothing and protective. Wrap-around sunglasses are helpful and occasionally a face and nose mask may be necessary. Monitoring of pollen forecasts and remaining indoors during mid morning and early evening (when pollen counts peak) will help. Taking an immediate shower and change of clothing after extended outdoor exposure will reduce pollen levels transferred indoors. Additional prophylactic medication may need to be taken on days when pollen counts are excessively high. When travelling by car, be sure to close the windows and put on the air conditioner to filter out pollen. Special pollen arresting filters and ionisers in the home are expensive and often ineffective.