I don't know. The passengers all had to sign a waiver that stated pretty clearly that the submersible was experimental, was not certified by any agency for safety, that there was potential risk of injury, including death, etc.
I think the waiver is meaningless if there was fraud, which it appears there was. If Oceangate was informed that their vessel was not safe, and they didn’t share that with people that PAID (no less), they can’t them require them to waive their rights to litigate.