A staff member is allowed to handle his own report as long as he/she does so properly, that is explaining to the person what rule they broke and why they are being warned. If you feel like the person handling the report didn't do it properly you can report them on the forums, also if you don't wish to publicly shame him you can try and talk to him on discord or steam. If he doesn't respond on either of those platforms either he probably deserves to be reported on the forums.