First:John was gay before the Cupids came and made him fall in love with Mary. Then after she dies he goes back to being gay  and ends up falling for Dean.

Second:Dean is taken somehow wheb he was young from John and years later they meet up again but John doesn't realize he is his son but Dean does and says nothing.They become lovers and there something about buying a house and a big bed that was built by Dean I  think.john discovers that Dean is his son and leaves Dean and Dean goes to the house.John eventually comes back and just accepts Dean as his lover

Three:Dean is taken by a human,who wanted Sam but Dean sacfriced himself, who abuses him and manages to get away from him and is discovered in Sunnydale while John and Sam search frantically for him. Dean tries to get ahold of his family but can't.He is taken in by Oz's family and becomes close to him and has some conservations with Buffy,Xander and Willow>i think even Jesse was alive.Saved by Dean maybe