Terry was way more coherent than Brandon, even in his most incoherent moments. Though it did vary a lot, and overall, most of what he said made sense (by far). And I don't think it was the medication either, because he was coherent when he was already homeless. His interview is a good example of that. Without knowing him, you wouldn't think that he's schizophrenic at all. Really, I think Terry was mostly sane, and his overall worldview made a lot of sense, actually.
https://yewtu.be/watch?v=HXwNTw4I6Ok
https://yewtu.be/watch?v=LTiRWN5T0Gw

Brandon, on the other hand, probably doesn't even know who he is most of the time, and probably gets injected with every known drug before public appearances.