If this were a matter for a vote, as you appear to suggest, Dan, then I would vote against your proposal. He's not being threatening, just wrong, possibly existing in the universe of his own, if you know what I mean. There are billions of highly-functioning adults who have beliefs of some sort of another, like being sure that that one guy parted the Mediterranean to make way for him and his friends to walk on the bottom; others are sure that their guy could glide on water and feed everyone with a baguette. Others believe in forced vaccinations and government conspiracies. At least we have precedents for those.
On the positive side - FDA just cleared a 2-minute COVID-19 antibody test. It's serological, which means you have to have your blood drawn for testing. Testing positive means one has had the virus and has developed immunity.
https://www.axios.com/fda-coronavirus-two-minute-testing-kit-bodysphere-a665429d-488d-4edf-bd36-9180e2a06e4c.html