There is no proof of him hacking, just saying he was. If you still want to report this players, post a thread here!
If he did report it, this would not be enough evidence. You can never use screenshots to report hackers, you need video proof.
What you need to do, ask him to play a round with you, but first download a recording software (maybe www.bandicam.com) then play with him, and once you go to fight him, or see him fighting, ect. Start recording.
As people stated, you need more proof, like video evidence. if you want to report a player, the Discussion area isn't where you place it. Place it in the reports section.