Hi Sue!
Since your grandson is already getting the Mickey character experience at Chef Mickey's, I would recommend the Hoop-Dee-Doo Musical Revue over Mickey's Backyard BBQ.
The Hoop-Dee-Doo Dinner Show is incredibly fun for all ages! The performers are great, and the skits are actually pretty funny! I like how in addition to performing on stage, they'll get involved with the audience singing, dancing, serenading, etc. It's pretty interactive and much more engaging than say, the Spirit of Aloha show, which was too boring for my kids (ages 6 and 2).
They do call attention to those who may be celebrating birthdays or anniversaries, so you should get your moment to shine. And who knows? You may even be asked to join in the skit on stage for the Grand Finale (smile)...
The food (all-you-can-eat fried chicken, ribs, mashed potatoes) was excellent also!
So give it a shot! You, your grandson, and the rest of your family should have a memorable time!