I'm sure you are aware that hygiene is critical - particularly if he is susceptable. Ensure he has his own towels, flannels etc - also make sure he isnt rubbing his eyes too much. Infection can spread from noses so make sure he's not picking that area as the infection will spread round face.
He may have a weakened immune system - vitamin A is very good for the eyes (in beta carotene form which is water soluble) and potentially vitamin C and E aswell to provide antioxidant cover. If you take him to a Kinesiologist they can test for nutritional requirements which suit him.
In terms of soothing it already, I have heard (but cant vouch for it) that hot used teabags (without milk) are very good (!!) There is a product called Silver Shield from Natures Sunshine Products which is a natural antiseptic and (in my view) preferable to antibiotic creams