Caught up. Thanks again for the release.
Still dealing with the death of family members myself. I'm quite thankful for this different approach to the matter. Not sure it is helpful, but it doesn't hurt to think of it in a different manner.
The question posed is, what is a relationship to a person? Saeki works with the idea that their relationship is based on events already passed, and he enjoys those. It could be just hanging out with his grandad is just that. Reliving the past, so protecting that is more important to him and his grandad than if he'll see him the next day.
Quite sentimental, but understandable.