I think it's important to note that Dave and the player themselves aren't the same person. Dave might be okay with Tyson the way he is at the start of the story, but that doesn't mean that Tyson has no issues that should probably be resolved. I played through his route pretty recently, and it was clear to me that he still has problems, even if he isn't lashing out at everyone like he did when he was younger. Obviously the player can't control what Dave thinks, but they can to an extent control what he does, and I feel like just by having Dave interact with Tyson more kind of helps the latter realize that there are still things about themselves that they need to come to terms with. I guess what I'm saying is that I don't need the MC to want to fix them in order for me to want to fix them. As for why I like Tyson beyond that, I guess it's a lot of small things really. He makes fun of Dave, but you know he would probably be the first to put himself in danger to save him. He's blunt, he has a sense of humor, he has a sort of complex pre-existing brotherly relationship with Dave, and he's one of the last connections Dave has with someone important to him. He's like an onion, he has layers, or at least I think he does, and I like that in a character. Maybe I just enjoy characters that are rough around the edges because I think they're fun to interact with, I'm not entirely sure.