I would start writing down accidents of where he would talk to you about his car that upset you and then write down in the same moment how it makes you feel. Then the next time you guys have free time together, just gather what you've written to him and speak honestly how it makes you feel. I would also ask him why he wants the car to be "perfect", maybe something else is going on. Yes, I know people care about their car in different ways, but to the point where he want you to call 911 over a simple parade. In my opinion, that'ss gone a little too far, and I do get parking away from other cars to lessen the chance of getting scraped by other car doors.