Legal Question in Intellectual Property in California

"Plagiarism" is something you are scolded for in high school. Also, it's unclear from the facts why there can be a suit for "defamation," but that is a recognized legal cause of action and your friend could indeed be facing such a suit, but again, based on the limited facts given, I don't see how any of this supports a suit for defamation. I'd suggest rather than filtering the limited information given through you, your friend should seek legal assistance directly and immediately. Among other things, you say "is being sued" -- do you mean (1) has been thretatened with a lawsuit, or (2) has a suit filed against him and has received a summons and complaint?

If the former, further reflective, informed and relaxed analysis is recommended, to determine whether the prospective plaintiff has a serious complaint or is just blowing smoke.

If, however, a suit has been filed and served, "your friend" had better seek immediate legal assistance. Being sued is far different from being threatened with suit.

I agree with Bryan. More specifically, I would say that it would be truly newsworthy if a lawsuit was filed claiming "plagiarism," as I've never heard of that being a cause of action. If, as you say, someone other than the copyright owner is suing for copyright infringement, then the plaintiff has a big problem. I looked briefly at one of the clips, and I also see no basis here for defamation. But as Bryan said, the one clear thing is that the defendant (if the lawsuit was filed or seriously threatened) should seek legal counsel. If it is a baseless copyright lawsuit, the prevailing party may recover the costs and legal fees for defending against it. If a suit in only threatened, but there is concern that it may escalate, an attorney may also be able to counsel whether to seek a declaratory judgment. Seeking legal counsel is also a good idea in light of the legal fight the plaintiffs are having over who owns the copyright. But no matter who owns the copyright, there are a number of lawful uses that can be made of the work, even when it ridicules it. Again, an attorney can help your friend sort out whether your friends use is infringing at all, regardless whether there is permission from the copyright holder.

Best of luck to your friend.