Lindsay I agree completely with Melvin and Cynthia. I got the feeling from your post the family may not be a very large one and lack of participation on any side will wreak havoc. If this is the case, let me offer one more suggestion. DEFINITELY place him in charge of the event but suggest a "potluck" cookout. You could encourage family members to bring those dishes that remind them most of home and be sure to let you loose cannon know he has to provide everything the members are not going to bring. Once he gets through with this headache he'll never open his mouth again.

Renee