I doesn't matter what the AI model said, it was not real. The "victim" was dead and it could not forgive anyone. This "testimony" should not have been allowed in court.
If someone wants to watch fiction, it can do it in a more appropriate place and not in a court of law.
Family can read fictional poems, personal thoughts, videos or photo montages. They can put up a picture of the deceased, and make statements like if "Bob was here, he would say x, y, and z"
The point is to influence the sentence.
Provided that the family was very clear this was not historic video, and I think it was, then one can see how this isn't obviously out of bounds
That's why you have the family of the deceased reading tearful letters, crayon drawings from children missing their parents, and other things of that nature introduced during pre sentencing impact statements.