I'm pretty sure that almost everything that went wrong in Bruno's life had to do with himself (this does not exclude the fact that some people took their problems out on him), see, even though he was terrified of seeing Abuela again, he went in search of her, and for what? To try to take the blame and free Mirabel, and it made me wonder: how many times does Bruno try to take the blame to make a person feel better after a bad vision, saying it only happened because he gave the vision? If he was able to overcome his immense fear of Abuela to take the blame and free Mirabel, surely he would have been able to do it other times, maybe this was the beginning of everyone starting to associate him with bad things and that he made these things happen, because he was a good person, beyond the pressure imposed by the family and his peaceful nature, and said that everything happened because of his vision so that the person wouldn't feel bad, but over time it got worse, and he's not a confrontational person so he never got a chance to explain himself, especially after his last vision since that was when he ran away and everything was left behind. Edit: Bruno also seems to be someone who has gotten used to negative things and never tries to look for something different when a vision is bad, as we saw when Mirabel shows that he didn't saw the butterfly in the vision because he was thinking negatively, so he's probably missed other details before and failed to see something good that could happen in a bad vision, which also helped to give him a bad reputation.