The context here is a bit more interesting. The case seems closer to: Disney will send you copyright strike for a photo you yourself called Loki, after a number of successful takedowns on your cosplay photos for the Loki character.

I'm against the idea of DMCA for cosplay in general... But if he knew how the rules apply before, this seems like testing the boundaries / "I'm not touching you" game. He can contest the request through the standard procedure. It would get interesting if that gets rejected.