Hi, welcome to healthcare magic
The steroids are only necessary if he has signs or symptoms of asthma or
reactive airway disease ( persons who are not asthmatic may sometimes still be hypersensitive to viruses and have symptoms such as wheezing,
shortness of breath, persistant
dry cough).
Steroids can also be used to treat any autoimmune conditon.
They are not usually used in uncomplicated upper
respiratory tract infection because of the side effects associated with steroid use.
An viral illness usually resolves with fluid use, rest, medication can be used to suppress the cough and
mucolytic can be used in wet coughs and to help in nasal
drainage,a decongestant can be used to help with
nasal congestion, honey can also help coughs.
Antibiotics are not used in viral upper respiratory tract infections and should be used cautiously because they promote resistance to antibiotics. Indications of a bacterial upper respiratory tract infection are symptoms lasting longer than the expected 10 to 14 days that a virus tends to last, fever gets worse into the illness rather than improving , fever higher than expected in a viral illness (in viruses a fever can reach up to 103, tends to last only a few days).
You should consider speaking to your doctor about the steroids if you have concerns, it may be that there were signs of reactive airway.
I hope this helps and I hope your son feels better soon