Can't you make an anynomus call? I sure would! Here (in NV) it's illigal to shoot within so many feet of developed property, and you can't hunt unless its A season and B you're in a designated hunting zone owned by the BLM. I'm not sure what the hunting laws in MI are though. I would go online and see what the laws are, and if he is breaking them I would inform somebody. I understand if he came over and said "I'm worried that someone might shoot your dog if he was over here" but from what you discribed, he seemed really rude and threatning.

Be careful and keep Max safe!