Who ya gonna call...?

[Burgess, John]

I think you're stretching too far here... while some of the characters in 
GR are quite content to accept communion with the dead as fairly routine 
occurances, or at least those that can be achieved on demand, the book is 
silent on the capacity for most of the characters in that regard.  IOW, 
there's nothing terribly strange in finding that Theosophists and Herero 
are at ease in talking with ghosts or spirits. Would Slothrop, Katje, 
Beaver and  more "mainstream" characters?  I don't think so.

My own opinion is that he was willing to use this as a device because it 
well suited his story.  Whether it indicates a change of personal feeling 
is a judgment for which there is entirely inadequate evidence to decide 
either way.