I'm trying to remember this one trope wherein a character (usually one dying of old age/disease) leaves before their death.

Title mainly. I can't think of any other examples beyond this one time with a kind of obscure seinen that I forgot the title too. It was basically about this super powerful old dude who left his family and came back? but in the end its revealed that the only reason he left was because he apparently had a disease and wanted to spend some time with them before he passed and in the end after one last day spent with them, he picks up his bag again and leaves to pass on his own.