"One thing that has always perplexed me about Dr. Hill was that apparently, he ended up broke."
What I heard from another Napoleon Hill hero worshiper, (Dan Kennedy, although I only heard it once, so I may be off in the details), was that the reason Hill went broke was because he hated to ask to be paid what his work was worth. One of the few things that Hill was afraid of was having his reputation diminished. Because of that, he didn't want to be thought as "money grubbing", greedy, and other negative baggage that folks carry around about aquiring wealth.
Stone "rescued" him and put him to work training his sales men and women. That's where much of the audio that we have of Hill comes from - his training sessions with those sales guys.
If I find the exact reference, I'll let you know.