No harm in saying just what you said here, "I am the camp cook and as normal camp fare we eat lots of deep fried things, sausage sandwiches, smoked venison, bacon wrapped everything, burgers, dogs, etc." and admit that you are at a loss to plan and cook for him. Just make it clear that you aren't saying "don't come" you're saying you need his help so that he can have a good time too. With luck, he'll offer to plan and bring his own meals - at least he'll tell you what works in a camp situation and you can have your son cook. We plan family get-togethers this way - the vegans often bring their own contributions and the gluten-free lacto-ovo veggies bring theirs. The only concession I make at Thanksgiving is that I hold some of the potatoes aside so they can fix them the way want. And I've learned to put avocados on the salads because everybody seems to love them. Your mileage may vary.