Thank you for your query,
Cough especially during night after lying due to postnasal drip or due to an associated cough.
Examination of the throat and lung is important to look for any congestion and wheezing
If the cough id due to congestion or allergic oral antihistamines like chlorpheniramine
will be requires.
If there is any wheezing bronchodilators are effective and some times nebulization is required in wheezing.
So I advise you to consult your Pediatrician
for the examination and appropriate medication for cold and cough.