You're right, I missed that bit of news and misread your original post. So the new charges brought in October '22 are not for manslaughter, but for misconduct or neglect of ship officer. According to this release from the courts, this charge does not require the prosecutors to show gross negligence, so it sounds like a lower burden of proof must be met:
Federal Grand Jury Issues New Indictment in Conception Boat Fire . In November '22, Boylan plead not guilty, and I believe he is currently awaiting trial. (I'm an engineer, not a lawyer, so my apologies if my interpretation is incorrect or misleading).
According to this reporting from the LA Times in Dec '22, video footage has been recovered from one of the victim's cellphones, that shows the scene belowdecks as people were awakend and tried to escape. That video has a timestamp of 3:17 AM. Capt Boylan's mayday call that went out 3:14 AM. If these timestamps are correct, it paints a pretty grim picture of the victims' final moments. As far as I can tell, this video is not publicly available -- I'm not sure I have the stomach to watch it anyway. But LA Times reports that the family members of some victims have seen it, so it's out there:
As Conception boat burned, video shows divers trapped below deck sought way out. 34 people died
I have not found any relevant information since Dec '22. I tried to find court documents that would tell us when Capt Boylan's trial is set to begin, but did not find any. If a lawyer (or just someone better at searching than me) could provide this information, I would appreciate it.