well, he's probably walling, to be honest, but that's not from our server, so really, we can't do anything about it, nor do i care a whole lot.
in the even this was at our server here are a few things you should make sure to include:
1 STEAM ID
with out that, unless he returns, he won't be banned. go into your console, type "status" and you will see each players name and ID next to it, copy and paste it into the forums with the demo. Or you can remember their name, go to our stats site, keagaming.hlstatsx.com, and look up the players stat page from there, and link that to the forum post. I personally would always link to their stat page to give all of the info easily to determine if he's using a cheat.
2 the demo
that demo was small enough to post with your forum post, and not need to have uploaded to an external download site. in the message options below, you can upload files, up to 5mb i believe, that file was small enough to just post here.
3 use the admin section
you're in kea now, there is admin section, this is something to post there, so we can discuss it and others can't. if you have any further questions, please pm me in steam, i'm always around. peace.