He has registered a copyright claim. Anyone can register a copyright claim for anything. Registering a claim says nothing about the claim being investigated, verified, supported by evidence, legally binding, etc. Everyone who has posted in this thread could right now register a copyright claim for bitcoin's whitepaper, and they would all be accepted.
If it wasn't hilarious enough that someone claiming to be Satoshi (who has apparently abandoned everything Satoshi stood for) was shouting his identity from every platform he can find and suing people for not believing him, let's all take a moment to appreciate just how hilarious someone claiming to be Satoshi filing a copyright claim is. Let's also appreciate the hilarity of the BSV shills pumping BSV on the back of this fraudulent announcement.