John in Bloody Mary
Since John was not physically present in this episode and he was only mentioned in passing, his influence wasn't as noticeable to me as in some other episodes where it seemed as if John was driving the mission itself and was very present in the emotions and interaction between the brothers.
Though John wasn't physically present, he was mentioned twice. The first time was after Dean and Sam viewed the body in the morgue. Sam suggested that it might just be a "freak medical thing" and not something supernatural, but Dean responded, "How many times in Dad's long and varied career has it actually been a freak medical thing and not some sign of an awful supernatural death?" Sam replied that has never been the case.
Dean phrased it as "Dad's long and varied career." He was talking about his father's career and not his or Sam's, and even the use of the word "career" indicates a respect for the job. It's likely that John viewed this as his career, so Dean and Sam did also.
The second mention of John occurred later in the episode. As they discussed Bloody Mary, Sam asked, "Did Dad ever find any evidence that it was the real thing?" Dean replied: "Not that I know of."
They both considered their Dad to be the expert and seemed to measure knowledge by him. They obviously didn't think he was all-knowing, but it showed a respect for his knowledge. John was still their main source of information either from what he taught them personally or through the journal.
I thought it was interesting that Dean called the retired detective "sir." My first thought was that this was instilled in him by John, and I still think that's likely. There may be other reasons for appearing to respect authority such as to avoid attracting attention or to appear less threatening and gain more information, but whatever the reasons, I think that Dean probably learned this from watching John and working with John.
While this episode really didn't have a lot of character development for John, it did show that he was still very present in the minds of Dean and Sam and that he was still influencing them with the things that he'd taught them.
Thanks so much for all the help that I received from toolman33, withpins, metroid_warrior, claudiasharon, and nialla. claudiasharon did the first beta and nialla did the last, but the mistakes are my own, especially since I changed quite a bit, especially due to nialla's insights. withpins lived through numerous rewrites of this with me and metroid_warrior held my hand through the last of the rewrites and did the final proofread.
I'm so sorry this is a bit late.