Even if he knew, saying that would be a good way to try to get Harry to reveal something. What he would have heard from Draco is that Harry has a super-bright Patronus whose form he keeps secret; he would be curious. So I don't think this quote is strong evidence that Lucius hasn't heard about the Patronus from Draco, since it is pretty likely that he would say something like this even if he has.
EDIT: Actually, since he believes Harry is Voldemort, he probably thinks the Patronus light he showed Draco was an illusion, and not useful for getting out of Azkaban at all. If he thinks Harry is Voldemort he's unlikely, then, to pry for information about it in this way.
Also, Draco may be more inclined to separate his observations from the implications of his observations. He's a scientist now, don't you know.
That may provide Lucius with superior intelligence, relative to what he would otherwise have obtained from a child raised by a doting Darth Vader.
This is a new thread to discuss Eliezer Yudkowsky’s Harry Potter and the Methods of Rationality and anything related to it. This thread is intended for discussing chapter 81, which should be published later today. The previous thread passed 400 comments as of the time of this writing, so it will pass 500 comments soon after the next chapter is posted, if not before. I suggest refraining from commenting here until chapter 81 is posted; comment in the 12th thread until you read chapter 81. After chapter 81 is posted, I suggest all discussion of previous guesses be kept here, with links to comments in the previous thread.
There is now a site dedicated to the story at hpmor.com, which is now the place to go to find the authors notes and all sorts of other goodies. AdeleneDawner has kept an archive of Author’s Notes. (This goes up to the notes for chapter 76, and is now not updating. The authors notes from chapter 77 onwards are on hpmor.com.) When posted, chapter 81 should appear here.
The first 5 discussion threads are on the main page under the harry_potter tag. Threads 6 and on (including this one) are in the discussion section using its separate tag system. Also: one, two, three, four, five, six, seven, eight,nine, ten, eleven, twelve.
As a reminder, it’s often useful to start your comment by indicating which chapter you are commenting on.
Spoiler Warning: this thread is full of spoilers. With few exceptions, spoilers for MOR and canon are fair game to post, without warning or rot13. More specifically: