That is interesting. I had not made that observation.
In that part of his statement that I heard, he called her Patricia several times...always in context of his efforts to be in communication with her and get his points across to her that he was sorry about what happened to Jon Benet, wanting to do so before she died, wanting to be assured that she either read or was aware of his writings.
It startled me when I heard it. It sounded unlike what I'm used to hearing...Patsy is Patsy to the world, though of course her birthname is Patricia.
It fits with what you said he was trying to do...place himself inside their world. At first, he was gloating over having gotten the best of them. Most recently, it's like he was trying to participate in the grief in their world...whether grief all these years over Jon Benet, or grief over the recent passing of Patsy.