[The Scientist (OP)]

I have a friend who has flu for 6 days. Its getting worsen, from a sore throat to runny nose. Without taking him to the doctor, what advice will you give him? Usually what are the cases or procedures? Thanks lots for answering!

[rosy]

I am not a doctor, this is not medical advice. If you're concerned, consult a medical professional.

The NHS have this to say on the treatment of flu:

If you are otherwise fit and healthy, you can manage your symptoms of seasonal flu at home (see below). You will usually get better without treatment.

If you are in an at-risk group (see box) and have flu-like symptoms, or if your flu symptoms are getting worse, see your GP. These groups are more likely to suffer complications from flu. You may be prescribed antiviral medication (see below).

Antibiotics are not prescribed for flu as they have no effect on viruses. However, occasionally it may be necessary to treat complications of flu, especially serious chest infections or pneumonia.

Caring for yourself at home

Make sure you have plenty of rest and are taking paracetamol-based cold remedies to lower your temperature and relieve symptoms.

Some over-the-counter treatments can be given to children who have flu, according to the instructions supplied with each medicine. Under-16s must not take aspirin or ready-made flu remedies containing it.

Always read the medicine's label or check with the pharmacist that it is suitable for children to take.

Drink plenty of fluids while you are recovering. You may need to stay in bed for two or three days after your symptoms peak.

(They also mention antiviral medications, but AIUI these are much more effective at the very early stages of infection, less so after a few days of being ill)

http://www.nhs.uk/Conditions/Flu/Pages/Treatment.aspx