You don't just get "knocked out" from having the entire lower half of your body completely severed.
But indeed, it's probably because the grandfather died that everything reset again considering he seems to be a very core factor in all this.
Though I suppose this confirms he can indeed die despite looking so young for an elderly man, there's no immortality involved and such. I guess whatever power was given to him it's more or less something that affects his age.
Also I forgot to mention, what does his son and daughter have to do with any of this warranting Vintage to kill both of them? I suppose it could've been an accident or something but I have my doubts.