Hi Lily! Since you won't be visiting a theme park, you have four options. 'Ohana at Disney's Polynesian Resort has a character breakfast, as well as Cape May Cafe, at Disney's Beach Club Resort. 1900 Park Fare, in Disney's Grand Floridian Resort has a character breakfast and character dinner buffet. Finally, Chef Mickey's, in Disney's Contemporary Resort has character breakfast, brunch, lunch and dinner all served buffet-style.  I recommend checking the links provided for full descriptions of the type of food and characters you may find at each.

Some of the restaurants do a "celebration dance" once an hour or so, to acknowledge birthdays, etc., where the characters parade through the restaurant, special music is played, and guests wave their napkins in the air. Chef Mickey's and 'Ohana have some form of this.  You can also order a small 6" birthday cake upon arrival at the restaurant-just let the host/hostess know when you check in for your reservation that you would like to do this.  There is a reasonable charge for the cake.

Finally, you will definitely want to make an advance reservation up to 180 days prior to the date you will be dining.  You can call 407-WDW-DINE (407-939-3463) or make online Disney Dining Reservations.

I hope your son has a magical birthday at his special character meal!