Not a huge fan of the first half of this chapter, he's just too gross and rage-inducing. Second half is sweet justice, though I'm not sure if it's enough to make up for the first.
That's the way I felt when I first read this story. But at the end of the book, when I read what the artist wrote about the story, I reconsidered. Recently I read it again, and it is now one of my favorite stories.
In real life, the old perv would be contemptuous and creepy, deserving of no sympathy at all. But if standards are relaxed because this is just fiction fantasy, he can be viewed as a charismatic villain with an amusing degree of creep, entertainingly justifying each action with a pseudo-reasonable explanation.