Selling Bitcoin Cash as Bitcoin is fraudulent. Did your friend buy Bitcoin only to end up with Bitcoin Cash, or did he buy Bitcoin Cash thinking it was Bitcoin? The former is a crime that should be reported, while the latter could be chalked up to buyer's due diligence, or lack thereof, despite being a byproduct of legally and morally questionable marketing.

The problem with the Twitter issue is that the term Bitcoin isn't trademarked. It can't be said that the account is pretending to be someone else if there's no one who could legitimately claim the handle. It's free-for-all, and it just so happened that a hostile party got to it first.

That being said, I do hope something can be done about their marketing. They're free to claim that Bitcoin Cash is the closest thing to Satoshi's whitepaper all they want, and I would also have no qualms about them saying Bitcoin Cash should be Bitcoin. Saying Bitcoin Cash is Bitcoin, though, is not just outright misleading, but is also regrettably legal (as far as I know at least).