Just a quick update saying that things have been slightly better. The psychologist wasn't phased by the more extreme things that have happened recently, saying that his behavior afterwards indicate that it isn't as psychotic as it sounds. She has a plan for him and wants to meet with me more often to discuss how things are at home and offer up more ideas.
I also started to read The Explosive Child, and while I haven't gotten to the specific sections, I think that the idea of his anger sort of being a skill deficit is changing how I react more. So that's a good thing.
Also trying to fix any underlying anxiety. Poor thing.