"the dead body was his only shelter and stay in that most dreadful hour. His soul, stripped bare of all sceptic comfort, cowered, shivering, naked, abject; and the living clung to the dead out of piteous need for grace from the soul that had passed away...."See in text(The Were-Wolf)
Sweyn has realized what Christian knew all along: White Fell was a werewolf, intent on harming the family. Stripped of the conviction and anger that brought him there, Sweyn only finds shelter and “stay”—another word for comfort—with the knowledge of Christian’s loyalty and sacrifice. Because he misread the situation so poorly due to his skepticism of his brother’s intentions, Sweyn seeks forgiveness from Christian, who only ever sought to protect his brother.
"he had entertained a germ of hope, that grew apace, rained upon by his brother's blood...."See in text(The Were-Wolf)
The metaphor used here is of a growing seedling. A “germ” is a small, living substance capable of becoming a full organism while “apace” is an adverb that means “quickly.” Hope begins to rise in Sweyn that White Fell might still be alive due to Christian’s blood, which suggests that she may have been able to kill him.