Wow, that's... troublesome. I mean, he's going to have to prove that:
1. The dance is somehow copyrighted.
2. He's the owner of the dance, and not the producers of the Prince of Bel Air show.
3. Epic copied enough of the dance to guarantee a copyright violation there.
4. Putting a reference in a game is grounds for a copyright violation.
How did he think this is going to work?
For point 1: in all countries abiding by the Berne Convention copyright is automatic, you don't need to register or something. If you created it, it is copyrighted. Point 2 is much more important. Did he invent it, or the writers of the show? And does his contract with the company that produced the show allow him to keep his own work or is all done in context of the show in ownership of the producers? Point 3 is a usual limitation of copyright. The court must decide if the work is significant enough for copyright, or to trivial. And if it is significant enough, if Epic copied enough of it. And then there is fair use and similar.
Towards how he thinks it will work out? Well, how all these people think:
Step 1: make fuss
Step 2: ???
Step 3: profit!