In the original novel, Blatty gives the impression that Kinderman indeed is lonely for outside companionship, as you mentioned – outside, adult companionship that ideally would, like Kinderman himself, extol the value of well-made films. This is one reason why he tries to lure Karras and later Dyer to the movies. IDR whether the original novel mentions Julie, Kinderman's daughter, who has some prominence in the Legion novel and screenplay. But Blatty in The Exorcist definitely portrays Kinderman as hungering for intellectual friendship and perhaps something more.

I was thinking of a real friendship that goes beyond a common interest in amateur film criticism, something that might move from a hobby-based camaraderie to a "best friend" status. In The Exorcist it appears that Kinderman has no real friends – he loves his wife, of course, but "Mrs. K, she gets tired" so he has to go the the movies alone. This idea seems fleshed out a bit more in Legion, where beneath the banter, Fr. Joe Dyer and Det. William Kinderman do seem to have developed the potential Karras-Kinderman friendship into an actual, warm Kinderman-Dyer friendship. It's more now than just going to see films like "It's a Wonderful Life", it's an ongoing, caring relationship. Of course, then the demon/the Gemini step in and cut it short.

Thanks, Fr. … yes, Rennyo 01 is my blog, all the stuff is mine except where indicated. Thanks for visiting there. … Actually, The Exorcist book/movie and Legion book/movie are the only films I go into in depth on the blog.  They are also probably the only two films I've ever analysed with much attention – I keep coming back to them because the whole Blatty "Exorcist" world speaks to my personal beliefs as well as the nostalgia of my Catholic upbringing (12 years of RCC education, was an altar server, had a nun aunt and cousin priest).

The closest other stuff on the blog to The Exorcist is probably a few articles I've written on H.P. Lovecraft, but they are few and far between. I didn't know how to react to the recent collapse of Del Toro's planned filming of At The Mountains of Madness … heard both good and bad about the script, and then there was the hooplah about Tom Cruise being the star, which made me uncomfortable, because the novella doesn't really have a central character, other than the narrator … it's almost an "ensemble" tale with the weirdness being the story's real "star" …