The first fic is an Au J2 fic, It's a Tarzan type fic. You'd think this would be easy to find but I've looked through the tags here, at J2-recs, spnkink_meme and others but still can't find it. Jensen is on an island and Jared comes he doesn't speak to Jensen (that I recall), it's sort of dub-conish in that Jared just kind of starts touching Jensen and Jensen doesn't really know what to do and at first tries to stop Jared and talk to him but eventually gives in. It was short and I think it might have been from a prompt? Not sure though.
FOUND! Link in comments

The second I think is wincest, could be gen. Dean is taken to an alternate universe after they're trying to hunt a djinn. In the AU Dean goes to the motel and finds that Sam has been beaten and hurt, he goes to help but sees that Sam is scared of him. Turns out Dean is abusive to Sam and I think Dean is a serial killer, not a hunter but I could be mixing that up with something else.
FOUND! I found it buried in my bookmarks The Cancer Inside by purplehrdwonder

The third fic is wincest, Sam I think had either brain damage or some kind of mental disability. Dean took care of him and John is aware of their relationship, not entirely ok but understanding. There's one scene in particular that I remember -->
Sam and Dean think they have the house to themselves and after having sex they come down the stairs happy and carefree, John is sitting on the couch watching tv and as they come down they realize they weren't alone. One of them is shirtless and it's obvious what they were up to, John and Dean just stare at each other at first and Sam says something to break the awkward tention and they all laugh.


Hope someone can help! Thanks