It's a week since your child became sick. And he is not improving as per your expectations, so it is high time u get him evaluated physically by his Pediatrician. And why are u giving cough suppressant and nebulization at the same time.as it defies logic.
Next Steps
Get him seen by Pediatrician ASAP. Rule out his being with Asthma which needs to be treated as per protocol and not with self treatment.
Health Tips
Give pure honey as many times per day
Plenty of fluids.