Today the kids were playing dress-up. Matthew put on his raincoat, that looks like a fireman's jacket, and Claire was pretending to be an Indian. She told Matthew that they were a family and he was her teenage brother. He got mad because he didn't want to be an Indian; he was a fireman. Then Claire clarified: he was her teenage, Indian brother who was ALSO a fireman. Matthew seemed OK with this role.
Here is a conversation with Matthew.