Those claims are dubious at best. I strongly advise limiting statements to that which can be demonstrated, not just links to theories on the internet. Place them on the defensive. Remember when they said the jab prevented you from catching or transmitting COVID? That was false. Call it out. Remember when it was "two weeks to flatten the curve?" That didn't work. Remember when we were all washing everything? Turns out surface contamination isn't a major vector. Remember when they closed schools? Turns out kids aren't very vulnerable and not shown to be significant transmission vectors AND it showed parents how badly schools teach. You can't prove your statements. You can point out when their prior predictions were proven wrong.