Hi My Baby Is 3.5 Years... And With Little Weathet

Hi
My baby is 3.5 years... And with little weathet change he has cough n cold.especially late night when he is sleeping he used to cough badly... Plss telme some proper medication as im tired of goin to doc visits as they give antibiotics when his cough increases n telme right nw his immune system is not developed so all rhis vil go on til d age of 6-7 years