To be hoenst it wasn't clear long ago if Sadakiyo died or not. All we got was a car explosion and that wasn't in detail as many of the other previous deaths in the manga like when he killed Mon-chan with the brick over the head. And also he was dying from a disease as well.
How the hell did Sadakiyo survive that explosion? Can't anyone other than Donkey stay dead in this manga?
“If it were a third-rate TV anime, a dead protagonist can come back to life at the producers’ convenience. But the world we live in is not such a convenient place. Lost lives will never return. Because of it, we live in a world where a life is an irreplaceable existence.”