permission to have your family decide to "deepfake" you should be opt-in. also, the whole point of "deepfake" is to falsely present an object as true. In a documentary, this is troubling. personally, every instance of deepfake should come with a on screen caption of "deepfake notice of creation of event".
The difficulty is going to be who represents the deceased if the estate agrees to allow the deep fake against the deceased's permission. It's both of a question of who has standing to sue the estate and who is going to fund the legal costs involved.