Try to be patient. Purple makes some good points. You asked him to respond if he had time. If he read the letter (it was a long one), he might have just opened it, read a little and closed it til later. Even if he did read it but didn't answer, ask him to read it again before responding. Maybe you can talk about it in the car tomorrow on the way to the campground. If not, then set a time to discuss it or for him to write a response. As you point out, if you push for a quick response you get him in a bad mood and things don't go well.
Personally, I am beginning to question his ability to deal with important matters in his life. Remembering the gas station incident and then today's little argument, it seems that he is not thinking as clearly as he should be able to. Has he been checked for a physical problem for his emotional state?
