Flu can kill if it develops into pneumonia. DH didn't have flu. but he had the coughing virus. He coughed night and day for 10 days, he wasn't sleeping, eating or talking, his throat was so raw and he was exhausted from endless coughing.
Yes, by day 7, I was thinking about seeking medical help. The reason I didn't? Firstly he had a routine medical appointment booked for the second week of January. We have also been warned to allow an extra 2 hours for travel to our local A&E, one hour for the road works nearby and one hour to find a parking place. That would mean 2 1/2 hour journey to hospital plus 5 hours waiting to be seen. I decided he was too ill to be expected to cope with that.
Fortunately we had planned to go to our house in France for a few days, so we went as planned. We had a cabin booked on the ferry and only a short drive both ends. I had decided that, if he had to go to A&E, I would prefer to do it in France because queues would be shorter and treatment more humane.
In fact we managed without medical intervention, but I do understand why many people sought it.