Telling him to google, then providing exactly one link to the company that created USDC isn't really much of a refute. Maybe a link to an independent audit (as far as I can tell there are none).

Much like tether, there is no proof that they have anywhere near the currency they claim and folks that operate in that market are the ones shouting the loudest about the apparent fraud occurring. I've yet to see tether or usdc provide proof otherwise, it always seems to be a "we wouldn't be this big if we didn't have what we say we have" - bernie madoff style. And to get in front of it, an attestation != audit.