I think the most important connection that exists right now between Charles and William is the fact that sooner rather than later, William is going to have to step into his father's shoes as heir to the throne. As he's been preparing for this now for years bit by bit, I think it most likely has given William a good hands on experience of just what his father did and was trying to do and how hard he worked on it all those years when he was growing up and how Charles has redefined the role of Duke of Cornwall and The Prince of Wales and has left big footprints for his son to follow in.
Reminds me again of a quote by Mark Twain. "When I was a boy of fourteen, my father was so ignorant I could hardly stand to have the old man around. But when I got to be twenty-one, I was astonished at how much the old man had learned in seven years."
As the years go by, the memory of Diana fades more and more into the recesses of history. This statue unveiling will most likely be the last really public "memorial" sort of thing that is done.