When Danny Cairns developed a cough and a sore throat, he isolated himself at home in Greenock.
But after a few days, he was so ill he had to be taken to hospital by ambulance.
The 68-year-old died there last Thursday, telling his brother on a video call that he was "on my way out".
Mr Cairns is one of the first Scots to die after contracting coronavirus to be named publicly.
'My best friend'
His brother Hugh, who lives in the United States, said the ordeal had been a "nightmare" for the family.
"He wasn't just my brother, he was my best friend," Hugh added.
The Cairns family is one of 126 families in Scotland to have lost a loved one to Covid-19 already.
Across the UK, 2352 people with the disease have died.
Hugh told BBC Scotland that Danny was "pretty strong" and "didn't break down" when the brothers spoke last week.
Hugh added: "From the time of going into hospital within three days he was dead.
"His last words to me were, 'I'm on my way out mate'."
Danny's family said he was a healthy 68-year-old with no underlying health conditions.
Hugh's wife Faye said Danny had "started feeling poorly a little over a week ago", and was complaining of "a little bit of a sore throat and a dry cough".
But, she said, he was "very, very healthy" until then. "He just had a physical two months ago where he was given a clean bill of health", she added.
"He has a weight problem but the doctor was surprised he had no diabetes, no high cholesterol - he was very, very healthy."
New restrictions on funerals mean that Danny, who was very involved with his local church and was active in local community with his wife Eunice, will be laid to rest in a service restricted to immediate family.
Once these restrictions are lifted, Danny's loved ones are planning a remembrance service which can be attended by all those who would have liked to have attended his funeral.
Hugh described the coronavirus as a "demon" you couldn't see, adding: "It's taking so many lives.
"You start to get a little bit paranoid about it. You are afraid of the unknown."