It’s improbable but if they ever behave anything like dogs not 100% impossible.
I’ve encountered an older dog that really really wanted to have puppies that stole a kitten from a litter and tried to raise it and feed it and made no attempt to eat it.
and there appear to be real reports of domesticated dogs adopting and nursing neglected children.
Of course dogs have the aggression dialed way way down such that they may be way way more likely to do that.
I’d argue that a she-wolf that’s recently lost it’s puppies instead finding some other small mammal to adopt is merely very improbable.
Mammal nursing mothers, even from fairly bloodthirsty species) can be surprisingly willing to adopt infant creatures of different species, even ones they’d usually snack upon.