So let's get this right.
These people were sent down in a sub which looks to be made by one of those overconfident and extremely dangerous idiots, it has no certification whatsoever, is controlled by a £5 gaming controller, is so primitive it literally has zero internal systems, has "70-96 hours of air" (which I will put £100 on being absolute tosh), launched from a vessel which has zero recovery capabilities and no communication methods. Going by the video posted earlier the entire vessel is a stainless tube with all manner of crap literally just bolted to it, and now the people in it have no hope apart from the various external agencies helping.
To be clear, I know that type of person extremely well and I can spot them a mile away. This man has likely been told many times that his sub is a pile of crap, has ignored all advice and carried on anyway because he knows best and is well aware that out at sea he's not governed by law. His contraption will be built using all manner of things that are either unsuited for this work or only barely scrape by. It's a miracle that his first dive was successful.
My prediction is he's going to be held responsible for this and the investigation will reveal what an absolute idiot he is and that he ignored many, many signs along the way and did it anyway. His whole setup is an amateur hobby grade dumpster fire of a company. Mark my words.