So sorry to hear about your sister, I know that has got to be hard on you.
I really don't think that you can ever fully prepare yourself, even if it is "expected". That is the way that it was with my mom too. This may sound like I am nuts..but, after my mom died, I convinced myself that she wasn't dead. At night, when I couldn't sleep for thinking about her...I would say to myself..."She is at home asleep, safe and sound". It was the only way that I could deal with her death. I finally came to terms with it. Which is a good thing, because she passed away in 1997.
As far as Patsy goes...yeah, she had a degree of acceptance of JB's death, way too soon. Another example is when Fleet yelled from the basement.."WE FOUND HER! CALL AN AMBULANCE!!!" And, she didn't even budge from the couch that she was sitting on. She KNEW that JB was dead...that is why she didn't come a running. Any other parent, upon hearing the words..."WE FOUND HER! CALL AN AMBULANCE!!"....after finding a ransom note, and their child was presumed missing....would RUN not walk to their child, hoping that they could do anything at all to help them. IMO...if there had of been a REAL intruder, and a real Ransom note...and Patsy heard the words..."WE FOUND HER! CALL AN AMBULANCE!"...she would have thought that JB was hurt...not dead.
Never heard of calling an ambulance for an already dead person. When my mom died, we didn't call an ambulance...we called the funeral home.