Sam and Dean have traveled the entire lower 48, some bits of Scotland, been through literal Heaven and Hell, have an actual Angel of the Lord (poor example of one) riding shotgun with them. They leave a wake of chaos in their path, in their pursuit of helping people (hunting things, family business) and in that wake are the people who have suddenly found their world turned upside down and shaken vigorously. Families are left to attempt to pick up the pieces of what's left of their lives; they mourn the loss of those attacked by whichever boogeyman of the week it was. Sometimes it's a demon's meat-suit (their lover, parent, child) sometimes without even a body to bury. Some turn to religion, becoming fanatical and angry (scaring the neighbors in the process); others turn away, questioning 'why?' Many become paranoid.
Could it happen again?
Will it happen again?
How do I prevent it?
Where do I even start?
And one very commonly asked when an answer is found: What the hell is half this stuff?
Google isn't always helpful, but slowly answers are found, as are kindred spirits. The Winchesters have no idea how many former victims are now hunters, or at least have been moved to help other hunters or other former victims. They even have a small fan base (independent of Chuck's books) that include some of the children they helped; many who now have a sort of hero worship for the brothers (one teenage girl still moons over the tall, dark, handsome men that saved her family from a poltergeist). Chuck's books don't help the matter in the least. They are passed along through word of mouth as one victim picks one up out of curiosity, then buys every volume her local book store owned when she recognizes events that happened to her and her husband that night in an apple orchard. Victims share the books and they talk ("I was there", "this one was about my dad", "scariest night of my life", "they saved me and my son"), most of the Supernatural fan-base stems from former 'clients' of the brothers, weep as they read through to Dean's brutal send off to Hell and are astonished when, a long while later, the books start back up again (Not that the Winchesters know that).
The books, the web forums, even a few couples who met in the aftermath of their disasters just to talk managed to regain a type of balance. They weren't crazy, they weren't the only ones to have gone through something, and things can be okay again.
Life eventually goes to some sort of normalcy for many, albeit with more precaution and a newfound respect for the supernatural. In every town, cops scratch their head when witnesses suddenly won't cooperate while some neighbors become confused when they notice lines of salt on the sills or rather demonic looking symbols peeking out from under rugs (one child even took to throwing water on guests when they entered and declaring them 'okay' when they didn't sizzle). Not everyone knows they've been helped. Some only know that two men with official looking badges showed up, left suddenly and then actual officials wound up finding a burning grave or blood-ridden hotel room.
If asked, most would say they could live many more lifetimes happily without hearing those names ever again, and several would be all too happy to help catch the Winchesters that (in their eyes) ruined their lives. Many families just want answers as to why their loved one was found with a fatal knife wound in them, how could anyone defile a grave in their sleepy town, and what was it exactly that led to that household suddenly becoming paranoid and withdrawn (or suddenly missing members).
But answers are hard to come by, and many of the people who don't like the Winchesters are shocked to see them on TV as serial killers. The eventual news of their deaths bring many of these people closure on that part of their life's upheaval. Good triumphs again, no need to worry further, all is okay in the world once more.
Dean and Sam are still alive, (and trying to get through their more metaphorical hells) fighting all the evil things that go bump in the night, and leaving behind another wake day after day: more victims, more potential new hunters, more enemies. All in the name of helping people.
Yeah, I always read fanfictions and drabbles about the brothers, what people think is going on in their heads, why one ship is totally canon and all sorts of things. But I haven't really seen to much writing about the people left behind and then my brain kicked into overdrive and wouldn't leave me alone. So I wrote this out and y'all get a bit of my head cannon as to what happens when people are left in the wake of the Winchesters.