My good friend is a healthy & fit 24-yr old male. He bikes about 60-80miles every week, doesn't smoke or drink (ever), has no medical conditions, and takes no m

My good friend is a healthy & fit 24-yr old male. He bikes about 60-80miles every week, doesn't smoke or drink (ever), has no medical conditions, and takes no medication. He had a mild case a few weeks ago— tested positive for antibodies, felt like a really nasty flu plus trouble breathing but felt mostly better in 2 weeks. He is having persistent symptoms that are really affecting his day-to-day life. He experiences serious fatigue about two days a week, to the point where it's difficult to work, and has occasional brain fog. It's really scary, I'm worried for him. And now I really don't want to get it.