How does Huck help the widow?

In Chapter 29, remembering the times when the widow had bestowed her kindness upon him, Huck makes his way out of the wood to the old Welshman's door. At first hesitant to open his door to Huck, the Welshman realizes that Huck "has got something to tell" and lets Huck enter. Huck tells the Welshman and his two sons all that he knows, with the promise that they will not divulge his identity. Three minutes later, the old man and his sons are at the widow's house; first silence, then an explosion of firearms and a cry ensues in the dark. Huck flees the scene.