I was about to post pretty much what glover said. But I think I'll just elaborate. "Figure out what our characters are like". The fact that you have everyone sort of fawning over him from your perspective is a magnet for a bit of backlash. And sad but true, at least most of the people there would do no such thing. For example, Becca wouldn't ask about Trysten's backstory. Becca's character is severely messed up psychologically, not to mention addicted to narcotics. She's about as likely to ask "What's your backstory, Trysten" as she is to suddenly start making out with Dave. Same thing with Cole. When you talked to him, in that situation, Cole would probably have not even noticed him, or given the brief monosentence answers I've been using for all intercharacter interactions, probably "Shut it, brat" or something in that vein. Or he might have just had it and physically harmed Trysten. He's a dangerous alcoholic. As for your third point, "been through things most adults never will"... *points at Hero's Path, World Turns, Draco's Story/Friends/Quest, Galactic Files, Dark Waters, League of Heroes*
The problem most people here are having is you've made Trysten into a textbook Gary Stu. And if there's one thing fic writers love to do, it's to have a Stu Roast.