we can make a thread like, does the community support the following rule
"Civil behavior is expected from players on this server. We will not hand down punishment lightly, but repeated complaints against a user can result in a temporary or permanent ban at the discretion of our administrators."
give it a few days, make voting public, it's a rule if it gets majority support, and as you can see it gives you broad latitude to handle things as you deem appropriate. you then move forward from there and punish van the next time you get a complaint that shows something you consider inappropriately abusive
i think that's the best way to do it. im not going to tell you what you CAN do, since youre the one thats in the server and not me. if you want to just add the rule you want to the topic channel, and then boot van when you see him run afoul of it, you can do that too. i just think the best way is to put the rule on the books first