What could have caused Hokey Smokes to be unable to do most magic?

This is a question that he had given up on answering, yet it was the one that Twilight Sparkle seems to have picked up. She had even gone to Sweet Apple Acres, picking him up from there after his final day of work. What will happen when she tries to figure out how it happened? Will she try to fix it, after what he had done? Does he deserve forgiveness?

Another thing that he has to go through is a strange metamorphosis. This isn't one of the body, but one of the mind. After the events at Sweet Apple Acres, he is starting to change as a person. Is it the influence of Applejack? Will Twilight Sparkle have a similar influence?

This is the second part of the series, and the third story that deals with Hokey Smokes. If you would like to go read the other two, it's possible.