My friend may have been hacked

So tonight one of my friends logs in, refuses to return my tells, takes me off of realid friendlist and starts deleting some of his characters.

As he is usually asleep at this time of night, I don't believe that he is the one that is actually doing this. He has been hacked before. So my question is what can I do at this point if I believe that he has been hacked again?

His characters keep logging in, stand by the mailbox for about a minute and then log out.

I already opened a ticket in-game and emailed him.

Edited for behaviors noticed and spelling.