If there's evidence to child abuse but no testimony can you convict the parents?

My friend has been in an unbelievably abusive family, she has scars and burns all over her body from her parents, and she has a horrible disease that is predicted to kill her at the end of June. Her parents videotaped the abuse, and we have the tapes. The only problem is she doesn't want to be alive when the evidence is brought to the police. I was wondering if she is dead could i use the videotapes to get her parents convicted for all of the horrible things they have done to her? Also, she is 18 so i also need to know if they can be convicted for it while she is alive.