All of you saying the man is clearly mentally ill, I agree.
But then I would propose and do believe that the Qanon people and the trump-lovers are also mentally ill.
By my calculation, about a third of the US is mentally ill.
I am not kidding.
It is impossible to rationalize with these folks because they hear constantly on their "news" sites this false stuff. And it's a big snake eating it's own tale. They believe this false stuff, they hear more false stuff which feeds upon falsity and it just makes them more and more entrenched in their ridiculous "beliefs".
It's absolutely sick and disgusting what Trump, American Republicans (with few exceptions) and Fox "News" and OANN "News" tell these mentally ill people every day.
Your husband is a victim of a massive propaganda campaign. No one can tell him he's wrong. He needs help.
Usually psychosis involves beliefs that could be proven false to any other rational human being. We cannot get these type of people to see that they are delusional because there's just too many of them who cling to the same false beliefs. Their own families often do not think their loved one needs help because they share the same delusions.
My ex had an episode of paranoia which I took him to the hospital for years ago. It was scary how convinced he was of his clearly irrational thoughts. Nobody at the hospital thought maybe he was right, after all. Now I'm not so sure what the medical field would think of your husband. Some of them might agree with him. Heck, I work with people in the medical field who refuse to get the vaccine because they watch Fox News and believed Trump when he said Covid was a hoax.
Masses of people are currently having episodes of paranoid delusions and a third of my country backs them up and thinks nothing is wrong with them.
This is not just anti-vaxxers, but pro-Trumpers, who I think occupy the same area in a Venn diagram.
With the caveat that some people cannot be vaccinated for legitimate reasons.
And some pro-Trumpers might have originally been pro-Trump for a legitimate reason. I don't see a legitimate reason for anyone to think Trump is an even half-way decent human now.
But that's me.