My one month old infant has a cough and congestion
Consult doctor. By the time try this: Turn the bathroom into a steam room with the door closed and the shower on full hot for 4-5minutes. Steam helps to loosen mucus and relieve congestion.
Eucalyptus essential oil in a diffuser. Mix with distilled water. Diffusers can be found for 10-20 bucks at most pharmacies. If cough exceeds 3 days, consult md.