If retroactive healing can be done for loved ones who have passed and are back in the light currently, could that potentially heal what they died of and prevent their death, restoring them to life?

You are resisting this answer mightily but now that you are easing up a bit to be dispassionate once again, we must tell you that this is fully possible to have happen. This opens up a whole new avenue of possibilities of bringing people back from the dead. We would not say this idly. It will easily rank as the most improbable and provocative of things you are claiming, and we know you will want to know much more about the ins and outs of this, and we are happy to oblige. After all, it is time for humans to grow up and truly understand who and what they are, and what the possibilities are from a scientific standpoint, or allowable through physics, as well as the spiritual dimension and your standing with Creator of All That Is. However you look at this situation, there are answers that are meaningful and that fit within the natural energies and the interplay that are explainable from a scientific perspective. It is just that it will draw on new science and not current science, for the most part, to make this understandable, but there is a time and a place to learn the new science. It makes sense at the current time to know this because humanity needs all of the healing help it can get. So this newest innovation you have thought of, to bring people back, in effect, from the light through time-shifting to allow some healing to be done while still in the living as physical human, and then knowing that a future incarnation will benefit from the healing that was allowed to happen because it could be done while in the physical plane but otherwise the person would be off-limits as a light being currently, this opens up many new opportunities to help people catch up with healing they were not able to arrange while they were alive and still have the benefits for the next outing. And this will change their future destiny in significant ways, as healing does, because it is the answer for all problems, that once they are taken care of through healing, the entirety of one’s future will be different and benefit accordingly. Problems will not disappear on their own or fade with time. Karma will seek redress no matter how long it takes.