I believe there are 2 different lawyers involved... the grandfather's criminal defense attorney and the family's civil lawsuit attorney. And possibly a 3rd, with both a Puerto Rico and US attorneys working on the defense. It was my understanding that the video was provided to police, who shared it with the criminal defense team. The civil lawyer (the one representing the parents in the Today interview) likely has no "rights" to the video until or unless it is made public. The police offered the parents opportunity to view the video and they refused.
What I haven't figured out is whether that video shows the onboard location leading up to the incident, or an external view. Presumably an onboard view.
While I understand the family wanting to place blame elsewhere, and I do believe the grandfather truly didn't realize in the moment that the window was open, I don't see this as the cruiseline's fault. However, they will likely settle to keep it out of the public eye any more than necessary.