Hi Paula,
My family love character meals! Not only are they a lot of fun but they are a great way of getting autographs and having photographs taken with the characters without having to spend time queuing up in the parks.
Character meals are available at some but not all Disney resort hotels.
For dinner specifically you have two choices :-
1/
1900 Park Fare at Disney's Grand Floridian Resort & Spa with Cinderella, Prince Charming, Lady Tremaine, Drizella & Anastasia.
2/
Chef Mickey's at Disney's Contemporary Resort with Mickey Mouse, Minnie Mouse, Donald Duck, Pluto & Goofy.
I would definitely recommend Chef Mickey's for a 6-year-old boy. (Please note that characters are always subject to change)
Other restaurants located at the Disney resorts which my 7-year-old son enjoys are :-
1/
Whispering Canyon Cafe at Disney's Wilderness Lodge Resort
2/
Ohana's at Disney's Polynesian Resort
I hope that this has information has been of help and please ask another question if I can be of any further help.
Wishing you all a magical holiday!