Please read this I found it helpful too you can also prepare steam for your child and ask him to sit in its proximity for atleast 5-10 minutes:
http://www.patient.co.uk/doctor/Nasal-Discharge.htm
The medical term for bloody nasal discharge is epistaxis.
Brown nasal discharge can be a sign that there is bleeding in the nose or sinuses. Which are hollow cavities in the nose. A brown nasal discharge is not normal.
(liquid) nasal mucus; nasal discharge; pituita; snot;
Clear nasal mucus or, "snot", is usually associated with allergies. If your nasal mucus is green or yellow you may have an infection and should see a doctor.
Strangles
It could only be Sinusitis, which is an inflammation of the paranasal sinuses. Some of the symptoms would headaches, dull facial pain, green nasal discharge and toothache.
its a light green discharge. kind of like cottage cheese.
Hemorrhagic nasal discharge
an inflammation of the mucous membrane lining the nose (usually associated with nasal discharge)
RHEUM (pronounced as ROOM)
Green discharge is a sign of infection. Go see your veterinarian.
Greenish nasal mucous usually signals a bacterial infection (often of the sinuses).