In the Superman mythos, Kal-El's adoptive parents on Earth, Jonathan and Martha Kent, are usually identified as the source of the moral grounding that caused him to use his vast powers not to bully others or conquer the world, but to serve and protect those in need as Superman. With his vast powers, it would be easy for Superman to subjugate the people of Earth. What prevents him from doing so, however, is the morality that the simple, decent Mr. and Mrs. Kent instilled in him while he grew up as Clark Kent. It was Jonathan "Pa" Kent and Martha "Ma" Kent who taught Clark that when he became a man, he must use his powers for the good of humanity.
In Jin Yong's universe, Kiu 3 Wai and his wife seemed to fulfill a similar role for Kiu Fung. Like Kal-El, Kiu Fung was an orphaned (or so he believed) child from a foreign place. He was blessed with great abilities and powers that could be very destructive if misused. Kiu 3 Wai and his wife, like the Kents, were simple, humble, and moral people who lived by a code of compassion and justice. Kiu 3 Wai and his wife showed Kiu Fung the value of kindness and justice when they raised him, and thus, when Kiu Fung became an adult and one of the most powerful men in wulin, he (like Superman) used his great abilities righteously and heroically.
The Kents are often regarded as the DC Universe's unsung heroes because it was their raising of Clark Kent that made him into the hero that the world knew as Superman. Likewise, shouldn't Kiu 3 Wai and his wife get a good deal of credit for how Kiu Fung turned out?
Final thought: Siu Yeun San, Kiu Fung's biological father, could destroy Kiu 3 Wai effortlessly in a physical confrontation. One was a fighter of supreme ability while the other was no fighter at all. Kiu 3 Wai, however, was a FAR better father to Kiu Fung than Siu Yeun San ever was.