There is absolutely no reason to hunt with a person who you can not trust. Come right out and flatly state the problem. If he gets upset - thank him and move on.
People only get one chance with me. I am a Hunter Ed instructor and Teach Like I hunt and Hunt like I teach. I don't deviate otherwise what type of instructor would I be?

Tell him flat out in a calm cool manner what the problem is. He starts to argue - stop right there then thank him and move on. Which means you are done with him. Your life may count on it!

JW