Read the whole thing. Very touching. But this bit stood out to me:

Dad wrote me a letter on my 50th birthday. It is one of my most prized possessions. In it, he encouraged me to stay curious. He said some very touching things about how much he loved being a father to my sisters and me. “Over time,” he wrote, “I have cautioned you and others about the overuse of the adjective ‘incredible’ to apply to facts that were short of meeting its high standard. This is a word with huge meaning to be used only in extraordinary settings. What I want to say, here, is simply that the experience of being your father has been… incredible.”

I can only imagine.