Need to have detail history.
If only sneezing no need to give any medication, if he has nasal blockage give nasal saline drops and if running nose can give anti histamine like cetrizine or CPM( as per his weight and age).
Next Steps
Consult pediatrician. If possible tele consultation at least.
Health Tips
Antibiotic is to kill bacteria. Its use is very specific. It is not a anti- cold medicine.
Antibiotic should be taken judicially as antibiotics resistance is big problem. Make sure you take it only when doctor suggests and prescribed.