What happend?

What happened is that he clicked on a server link (idk if the server was or wasent the server that he sent) and clicked on "verify", when this appeard :

He scanned the code, and it gave all the info of his discord account to the hacker that is probably "Anna Nuds#2219".

How to prevent it?

First : If someone send you a link of a discord server, watch out! maybe they will try to hack you!
Second : If that person have other social media and you can DM them, ask them what is in the link!
Third : Don't click on suspect links!