Dean would totally retire to be a small town sheriff. And keep the impala in the garage, because he mostly drives the work vehicle now. And ok so there is a family of werewolves, but they are the mostly-normal kind, not the heart-eating kind. And then get totally hit over the head (possibly literally…) by some local woman who works at the auto shop (where Dean goes to buy parts for the impala and complain about how the official vehicles get taken care). or the diner (where Dean eats all the time, habit). or the library (because Bobby keeps having idiot baby hunters call him for help when Bobby himself is too busy, or more likely, too annoyed, to take care of it). and she doesn’t care that he has scars on his skin or his heart, and that he still wakes up breathing hard, or some nights he sits downstairs holding a gun and waiting for something that never comes through the door. Including the entire week after she and baby Stiles come home from the hospital.
And when Stiles is seven and he comes home saying that he found a little brother (because Scott is one and a half months younger than him) and is going to be just as good a big brother as Dean is (because Dean always talks about Sam, and when Sam comes to visit he talks about Dean) Dean about loses it and his wife has no idea why he’s crying.
(She usually has no idea why he’s crying, even if her kid always seems to get it. Neither Dean nor Stiles cry when she gets the test results from the doctor. They make the exact same face and Dean says “well, ok” and Stiles nods with him and she wonders who’s going to take care of them when she’s gone.)
Now, the story as to when Dean was getting set up with a real, for-permanent fake identity he ended up as “Dean Stilinski”? That’s a funny one.
(Not to mention how he trusted the Argents, and fucking Kate, and then she’s off the map and he can’t find her, and those dumbass werewolf kids are gone before Dean can talk to them and promise to make it ok. And then Laura is dead and Derek Hale is back and his kid is getting into supernatural trouble and lying his ass off to his old man to protect his brother and his dad. Just like Dean would have done.)