I have a bachelor's on zoology so I can tell you that it isn't uncommon for mammals to sometimes suckle babies of a different species. I have read that in times before the advent of breast milk substitutes people would feed babies milk from any viable source; cows, sheep, goats, etc. Since infants receive valuable immunities from their mother's milk, these infants had an astoundingly high mortality rate but some did survive. And babies will suckle on ANYTHING so if a wolf's teat got near his mouth he would probably suckle on it. So it is possible however highly unlikely that this would work. It would require an extremely accommodating wolf and a lot of luck that the boys don't contract any viruses or bacteria. (unlikely in a forest) More than likely the wolf would have just classified the boys as "easy pickings" and eaten them.