He's probably talking about one of those "smart dns proxy" services. The way they work is that they return a proxy server IP for geoblocked domains, and the normal IP for everything else. The proxy server in turn figures out which server to connect to using the SNI header.
It's misleading to call it "change your dns to a uk server", but he's also not totally making it up either.
Yeah I'm not accusing them of lying, sure if they use a service that also includes proxying then that can bypass geo restrictions it just has nothing to do with DNS or the country the DNS server is in.
It's misleading to call it "change your dns to a uk server", but he's also not totally making it up either.