Hi Kevin,
My family was able to experience
Disney's Spirit of Aloha Dinner Show on a recent trip to Walt Disney World. The children in our party had a great time dancing, and my husband even got pulled up on stage to do a dance! I also have a
Tables in Wonderland Card, and I really enjoy the 20% discount on food and beverage at many Walt Disney World dining locations. You should first know that this discount is only applicable to the late showing of Disney's Spirit of Aloha Dinner Show, not the early one.
I called and spoke with a very helpful cast member who told me that probably the best way to ensure that you get the discount is to call and book a new reservation with a credit card and your Tables in Wonderland card. Then, cancel your brother in law's reservation. The cast member said that since you have until 24 hours before the show to cancel your reservation without penalty, you can do this right up until the day before. You can call (407) WDW-DINE (407-939-3463) to do this.
I also understand that some people have been able to get the Tables in Wonderland discount at certain pre-paid meals by showing the card once you get there; however, I have never heard of this specifically at Disney's Spirit of Aloha Dinner Show, and the discount went back as a credit on a Key to the World Card. I am not sure that I would count on this working as the names will be different on your Tables in Wonderland Card and the dinner reservation that your brother-in-law made, but you could try it.
Have a great time planning your vacation Kevin - it is coming up so soon! Please do not hesitate to ask if you have any further questions.