Is He Too Trusting at the Beginning?

At the beginning, they're not establishing that he's too trusting. Well, he trusts sully. And it's always sully not trusting him. So i think it's just bad writing, because it goes completely against the theme. That's wha i'm saying, is he too trusting at the beginning, and then h eans, do not trust as much. But then in the end he does trust sully. I don't know what it's trying to say. He wants everyone to work together. The allo lost, all his lost moment is when he has the fight with sully in barcelona and leaves. Because there's something right about that.