No, actually, his statement is technically correct. In this context, "valid" means that the conclusion follows from the premises. If I say "A, therefore A" then that is circular, but also logically valid, i.e. every time the premise is true, the conclusion is also true (because they are the same thing!).
It's just not a useful way of backing an assertion, because since the argument uses the conclusion as a premise, it lends no extra strength to it.