You can all be the guinnea pigs for this new medical procedure but I'm fine focusing on a natural healthy body that can take on anything. I already had the COVID, it lasted about 2 days. The second day when I realised what it was I took Vitamin D and Zinc in the morning with 1g of Vitamin C every hour. It knocked it right out.
I too focus on natural health, although I am aware that at some point chemical treatment may be necessary.
The case you mention must have been due more to Vitamin C than to the other two components. It is a protocol that usually works very well when you have caught a cold/pharyngitis etc. 1 gram of Vitamin C every hour until you feel better or until you get loose stool (which signals that your body has enough Vitamin C and is expelling what is not needed).
For vitamin D the dose is not as important as the blood levels, I would say at least 60ng/ml but if they are 20 or 30 ng above better. In any case that is not achieved with one day doses but over time, unless you take 100k IU in a single day.
There are many studies on how beneficial it is to have optimal levels of Vitamin D to pass the Covid without symptoms or with few symptoms, most of them are compiled at
https://vitamindwiki.com/