~ Your muse now has the ability to bring a deceased loved one back to life perfectly (no decay or anything, just as they last saw them). The catch is, their loved one would have no memory of your muse at all. Would they do it anyway? ;3c
sad muse meme | accepting
As previously established, reviving the dead is something Xerneas is capable of doing. For various reasons he does not. Let’s assume his biggest reason ( the life/death cycle ) didn’t apply to this instance. Yveltal didn’t exist and it was just him running the whole shebang.
Xerneas would have to be in an immense amount of grief for revival to be considered. Reviving the deceased would be an impromptu decision made right after his loss. It would have to be made in the first few minutes while denial was still kickin’.
Ultimately, though, Xerneas is more selfish than he is selfless. If bringing a loved one back meant they had no memory of him, he would rather they stay dead. The only possible exception I can see to this would be Freya, and that would be ( as they say in Avatar ) if the world needed her most.