Kiwi Herb are on the internet and do a fab product called "De-Stuff" for kids. It's herbal/natural remedy for ears and nose. It helped my eldest to stop having so many ear infections and the ones she did get, a combo of medicine and De-Stuff helped them clear up quicker. Now when she gets a bit snuffly we dose her with De-Stuff straight away and it usually doesn't develop into anything major.
It has a dosage on the label for little ones - you can always give less than the stated amount if that makes you feel more comfortable using a herbal product iygwim. Best of luck