In chapter 8 of the Saga of the Völsungs, Sigmund (in wolf form) attacks and almost kills his son Sinfjotli (also in wolf form). Sinfjotli is only saved when Sigmund is pointed to a miraculous herb by a couple of weasels and a raven:
Then Sigmund rushed at him so hard that he staggered and fell, and Sigmund bit him in the throat. Now that day they might not come out of their wolf-skins: but Sigmund lays the other on his back, and bears him home to the house, and cursed the wolf-gears and gave them to the trolls. Now on a day he saw where two weasels went and how that one bit the other in the throat, and then ran straightway into the thicket, and took up a leaf and laid in on the wound, and thereon his fellow sprang up quite and clean whole; so Sigmund went out and saw a raven flying with a blade of that same herb to him; so he took it and drew it over Sinfjotli's hurt, and he straightway sprang up as whole as though he had never been hurt. There after they went home to their earth-house, and abode there till the time came for them to put off the wolf-shapes; then they burnt them up with fire, and prayed that no more hurt might come to any one from them; but in that uncouth guise they wrought many famous deeds in the kingdom and lordship of King Siggeir.
Source: The Story of the Volsungs, translated by William Morris and Eirikr Magnusson
Is it Odin - who is commonly associated with ravens - that intervenes and heals Sinfjotli? If so, why? Wouldn't Sinfjotli make it into Valhalla, had he died as a wolf?