Unless the SEC can show that his postings moved the stock and he was buying and selling in concert with the action, I don’t see how there is anything here but a grandstanding agency rushing into the spotlight. It will close the file as soon as the publicity quiets down.
Since he is an executive -- an insider if you will -- if his actions can be shown as an attempt to influence the stock price (whether it actually moved or not and whether he then took advantage by buying or selling or not) then he was in violation of the law.