Vibes to DR John G's sister Linda and her husband, Mike.
There have been some articles in the alternative press about how to treat Covid naturopathically. The ones I've seen are in the online magazine Vitality, which is based in Canada. The recommendations often include vitamin D3, vitamin C, quercetin, astragalus, vitamin A. There are quite a few anti-viral herbs, actually. Many people are low in Vitamin D and benefit from supplementation in general. This approach can be used for prevention as well as treatment of an existing condition.
I hope Linda and Mike find an approach they feel comfortable with and meet with success!