It is understandable to worry when your child has a persistent cough, but please be reassured that this is a common issue with highly effective solutions. Rather than over-the-counter immunity boosters, which often lack proven benefits, focus on natural ways to strengthen his immune system. A balanced diet rich in vitamins (especially Vitamin C and D), zinc, adequate sleep, and good hydration are the best natural boosters. Because this cough has lasted a long time, it is important to consult a paediatrician or pediatric allergist. They can evaluate him for common, highly treatable conditions like asthma, environmental allergies, or post-nasal drip. Avoid self-medicating with antibiotics or cough suppressants without professional guidance.