YMS said in the most recent Sardonicast that he personally would never come face-to-face with Derek since he's too unpredictable. He also claimed to be in close confidence with Pewdiepie, sharing the "lore" of Cool Cat and Daddy Derek, but considering he's a cow himself I don't fully believe him - I think it's more likely that he sent Pewdiepie a long series of paragraph messages through Twitter and may have received a message like "thanks for the heads up" or "wow that's crazy" as the response.
Either way, Derek is shady and vaguely creepy enough that I would dissuade any YouTuber with a significant audience from associating with him. I think it's within reason that Derek will get himself into some scandal within the next five or so years, and YouTubers don't want to get covered in shit by standing in his splash zone.