Hi..
Welcome to HEALTHCARE MAGIC..
I have gone through your query and can understand your concerns..
As per your complain it seems that brown mucus-like substance running out of his nose along with congestion, coughing up black mucous and headache seems to be due to infection in the sinuses leading to
Sinusitis and as the sinuses drains through nostrils, therefore fluid/pus accumulation in sinuses can drain through nose..
I would suggest you to consult an Otolaryngologist and get evaluated and a thorough clinical evaluation and investigations like PNS view x ray or MRI scan can help in diagnosis and treatment can be done accordingly..
You can be advised a course of antibiotics, anti-inflammatory painkiller like
Ibuprofen, decongestants like Pseudoephadrine, do saline
nasal irrigation, steam inhalation and use a humidifier in your room..
You can also be advised decongestant nasal sprays containing
Xylometazoline or
Oxymetazoline..
Avoid spicy and chilled foods..
Do warm compresses around nostrils..
Hope this information helps..
Thanks and regards.
Dr.Honey Nandwani Arora.