He has a line where he writes

    return val; // val is `rvalue` here

This is the part that isn't accurate. "val" is a named reference and is not an rvalue. There isn't any "moving" up the stack that happens. He's likely confusing this with an expiring value (a subtype of rvalue) that happens in code like

    foo(returns_something());

The returned value from returns_something() is un-named and is about to die after this line executes (lives until foo's invocation unwinds) and so it is an rvalue. You can't have a named rvalue unless you std::move explicitly I don't think.