I don´t think John will die because of the thing I think he will die because he tryed to protect Sam (and Dean) that could be his final redemption
I think the reason the thing wants to kill the woman who are close to the winchester is going ages back. Maybe there was a betrayal from the Winchester clan and the result waa that someone got killed (maybe the person who got killed was a pregnant woman...don´t aks me why I think that) or maybe someone was unfaithful and a child was born and this child was the reason a war got started and the child got killed during the hateful war and now want´s revenge from both familys the Winchesters and another family we will learn about later this season.
Oh, I don´t know anything
