Thank you for your question.
I am Dr. Su S. and I will try my best to help you.
Viral infection usually subsides by 3-5 days.
Sometimes, it is prolonged but is often over in a week.
Bacterial infection can supervene in the post viral period.
So doctor has started antibiotic.
You can continue the treatment advised by doctor.
Please give him plenty of fluid & keep at rest.
Warm & liquid foods will be good.
I hope this information will be helpful.
If you have any query, please feel free to ask.
If you are happy with my answer please click on the Excellent/Good rating.
Wish his healthy life.