As I understand Nina had a sat phone
and stopped using it, so either lost
power and that would have ended AIS
transmissions, or it sank and that would end AIS transmissions also.
Not definitive information, and Nina did not have AIS anyway.
So OK, what more is there to discuss in this case?? Without finding the boat or the people, there isn't much else to learn from it, the known facts haven't changed, nothing new for some time.