No, he’s being a three year old. Kids are anal about stuff like that. I remember throwing a fit if my mom didn’t call my stuffed animals by the right name, or if she said I was four about two weeks before my birthday. I remember throwing a tantrum when she told a librarian I was seven-a month before I turned seven. 
Or I had to have my sash tied perfectly-it’s just kids. Kids are anal-they make a much bigger deal out of things. Relax-it’s normal.
Kids like to have control over their own environment. They like routine and rules-it’s comforting and a way for them to keep things in control. I believe there’s a word for it, but I don’t remember-oversimplification? Something like that.
I’m OCD and that doesn’t sound remotely like it.
Try chemical imbalance.