Isn't the central conflict character vs. character because Brad is in opposition with Gavin? How is the conflict Brad vs the rest of the world?
is it character vs. society if the the central conflict is Brad vs. the rest of the world?
I would say no, the central conflict is not character vs. character, or Brad vs. Gavin. It is Brad vs. the entire world/the nature of reality. Why? Because he can't accept reality. He has denied that his sister died. He's fighting reality in relation to his sister, Gavin, his mom…each conflict with a character is just an example of how he clashes with reality, due to his need to escape from it.