There was no secret this didn't pass any regulatory standards. The window on the front of the sub was only pressure rated for a third of the depth the Titan was going (and where it had gone before). NASA and Boeing assisted with the creation of the hull but refused to sign off on it being safe because there were serious questions.
Canada have said they are looking into possible legal action, but so far in their investigation it appears that they haven't broken any laws. The guy knew he was skirting safety regulations, he deliberately maneuvered into legal grey areas. Again, it is not a secret about any of this. He did it very openly.
Like both of us have said - the legal ramifications for OceanGate are likely to come from the families of the victims making a claim that the waivers aren't valid and that OceanGate was grossly negligent, and blatantly so (as is well documented). Wrongful death verdicts would give some chance of seeing some culpability for the families of the victims. A verdict in favor of one of the two billionaire families with victims onboard is likely to force OceanGate completely out of business - and... it honestly already is with how much bad press they've received and their CEO imploding in the middle of the Atlantic.
An attorney using social media to make content other than advertising content (and even that can be questionable)... is probably not a great attorney.
And again, what they were doing was really well documented. They are famous for not getting proper certifications shrugging their shoulders and carrying on with what they were doing. They used the previous successful missions to point at the safety regulations and laugh.