May Allah bless him with good health.
Most certainly a false negative. (Presence of an unusual range of symptoms)
Those doctors are describing it wrongly (however that's an academic discussion). Huge misconceptions are present among MDs regarding Covid19. There's nothing as such 'Covid Pneumonia'. A pneumonia is a pneumonia. Remember, Sars-Cov2 is not an illness itself, its a virus that can induce a broad range of disease process or no illness at all (asymptomatic).
There is no standard treatment for Covid19. Treatment strategies keep on changing; depending on the kind and severity of illness induced by the virus.
Neurological symptoms, often resulting in "Long Covid". There are so-called recovered patients who still do not have a sense of taste and smell, as well as experiencing brain fog, even after 7, 8 months of recovering. Mankind has not seen anything like this before. I hope he doesn't have blood pressure/diabetes history.
Totally. This is here to stay, for a lifetime unless a new mutation occurs that minuses previous strains. Do not depend on vaccine. That's a decade long plan for even a country like USA with all its resources at disposal. Precaution is the only way. Masks are not that bad after all.
Stay safe.