This is going to go the way of MH370, a big mystery that will never get solved or found. That sub had fail safe measures that would have made it surface during an emergency. This submersible had too many dives, stress relaxations, compressions and structural fatigue that finally caught up to it. They were more likely gone before they knew what happened.
In the unlikely event that it didn’t implode, it might have lost power and it is being bounced along the sea floor. If that is the case, then their air will be used faster due to the freezing temperatures and they are gone by now…..not to mention the air can’t be scrubbed by the compressors(like a rebreather).
IF, and that is a big IF, the sub is found……there is no way to rescue them, especially in this timeframe. I think the Navy are the only ones capable of such a rescue but there isn’t time to get assets into position once they do find it. They then have to figure out how to hook onto and raise it……this is pretty much impossible.
The absolute best case scenario here is for the sub did ascend and they just haven’t found it floating yet……time is a ticking if that is the case.
IMO, something happened (implosion) that caused them to lose contact with the ship. That is the more humane way to go rather than laying on the seafloor, in the cold pitch black while suffocating to a slow death.
I hope I’m wrong and they get these guys back but I have a feeling nothing will ever be found from the submersible.