Thank you so much for all your suggestions! I really am leaning towards something we can grill. His mom just needs to accept it now that I'm not one to slave away in the kitchen all day!
I'm thinking I might do hamburgers, baked beans, corn on the cob, maybe pick up a watermelon or something.
On a side note, we'll have something to do in the afternoon now if we run out of things to talk about. We had an F4 tornado hit our town last night, so there is lots of damage to drive around to show the parents.