@cromat: Well, the ending blurb puts it succinctly; what a person wants is what she’ll suppprt. Maybe a case of blue and orange morality. She is a witch who consorts with devils, after all, so what she thinks is good for a person doesn’t necessarily align with normal morals. Or rather, normal morals don’t cover the decision of whether or not to become a werewolf, so I take it as the matter of his age not mattering to her as this decision is outside the bounds of normal logic and morality from the beginning.
A human child leaving his human family is wrong for us humans, but wolf packs are apparently quite willing to adopt orphan wolf pups into their group. The reasoning of beasts is different from that of humans, and it was his decision alone to decide what logic he wants to adhere to as a werewolf who awakened his bloodline and can choose between.