I'm not licensed to practice maritime law, but I think the two countries most likely to charge them with a crime (US and Canada) will struggle to find jurisdiction for said crime, and as a non-registered vessel, it isn't required to confirm to SOLAS regulations.
Civilly, however, it's going to be easy enough to make the company disappear, and families might be able to find recompense from whoever insured OceanGate (assuming it was up on it's insurance bills, which might not be a given). I think it was negligent to sell tickets on such an excursion because I think it implies a base level of safety, but depending on the waiver --if OceanGate said "This is experimental and completely unregulated and untested. We can't promise you won't die", for example-- then the estates of participants might be screwed regardless. That will be argued by big dollar attorneys on both sides, and doesn't seem immediately clear that either would prevail. I suspect the insurer would be motivated to settle out of court, but families might also be so motivated.