"Do we have to over-analyse everything to death?:

YES !!!!!

LOL! Sorry, but some of us like to open up the back of the clock to see what makes it tick. That doesn't mean we don't appreciate life's mysteries; it's just that the lack of understanding of those mysteries gives us more consternation than delight.

As for the Oscar mystery, I think there may be other (or, at least, more) factors at work here than the emission of odors by the dying body. For instance, many of us cat lovers have observed the phenomenon that a cat will, when entering a room full of guests, seem to be most attracted to the person who likes cats least. Why? Not because the cat wishes to annoy the cat "hater", but because he/she is least likely to annoy the cat (by picking it up, petting it in a way it doesn't care for, or otherwise disturbing its routine) -- the cat "hater's" space is the calmest spot in an agitating environment. By the same token, when Oscar makes the rounds of his nursing-home environment, I believe that he would spend the most time curled up on the bed of the patient who was least likely to disturb his rest: the patient who was moving around the least because he/she was near death.

On the other hand, perhaps the cat curls up on the beds of several different patients indiscriminately; perhaps the nursing home staff's perception that he spends more time with near-death patients is simply a bit of Monday-morning quarterbacking??? They've been right 25 times, but I wonder how many times they've called up relatives of a patient Oscar has curled up with, to alert them to an impending demise, only to have the patient live for several more weeks or months... or years?