Do you think in a fantastical scenario where a good person dies (recently or years ago, known to you or unknown to you) that you would be morally obligated to bring them back if you could instantly and without issue for yourself and the person?
Or is it merely something kind but not obligatory?
No. The idea that you are obligated to help is dangerous, since it can lead to you basically destroying your own life by doing nothing else. This is especially true in hypotheticals where you are the only person with a superpower, since there’s only so many hours in the day and if you try to take the weight of the world on your shoulders you will be crushed.
I mean, there’s a reason that effective charity is done by groups; the larger the better. What is crushing for one person is easy for ten thousand.
Morality is itself a blurry object. Good and bad, right and wrong are not objective. We may disagree on the “goodness” of a given person or the net positive effects a given person has on the world, or how their actions in a world in which they no longer belong will play out. If we brought back George Washington, how can we guess what value he could provide us, or whether he would simply go insane from the culture shock?
No, the dead are gone and need to stay that way. It is not at all a matter of morality but one of practicality.