Dean never gave his parents the journal and colt. He never said he was going to see them in Heaven, just that he was going to take a drive. And it shows that he didn't go to see his parents because as he was taking his drive, Sam was living his life (time works differently in Heaven) and at the end of the drive, Dean stops at the bridge. That's the only stop he makes, and no one was waiting for him on the bridge either. Dean gets out of the car, stands on the bridge and THEN Sam comes. Maybe you should watch the show before writing about it.