Helper figures in fairy tales have some serious mojo. What's that, you need a flying ship or magical apples? They've got it covered. You want a helping of backstory to go along with that? Sorry, you're out of luck.
Here's the thing: we know more about what helpers do than who they are or why they're so helpful. Take, for instance, Faithful Johannes, who swears to act as foster father to his dying king's son: "I will not forsake him […] and I will serve him faithfully even if it costs me my life" (Faithful Johannes.20). What did the king do to earn this dude's loyalty? Who knows? To be fair, the fact that his name includes the word "Faithful" is a pretty big clue as to his character, but the why of the bromantic loyalty is left rather mysterious.
Sometimes helpers start out mysterious, but then begin to make sense. In "The Golden Bird," the youngest son is kind to a fox who helps him achieve everything he sets out to do. But there's more to the story: "Once again the fox implored him to shoot him dead and cut off his head and paws. This time the prince did it, and no sooner was it done than the fox turned into none other than the brother of the beautiful princess, who was finally released from a magic spell that had been cast over him" (The Golden Bird.204). A-ha, we see a little "I'll scratch your back if you scratch mine" thing going on here. But the fox, like other helpers in the tales, was also keeping an eye out for who was kind rather than cruel.
So whether your helper figures are servants, animals, old men in the woods, or old women in the woods, the bottom line is to treat them well. They may have their own reasons for helping you, but you'll never even get close to knowing why (or close to your goals) if you're a jerk right off the bat.