Hi April,
I know first hand what its like to have a child that necessitates a lot of attention while making sure siblings feel special & not left out. It can be very hard on your heart sometimes & you're an extra special mom for wanting to make his BD special for him.
WDW is the best place ever to celebrate a BD. Make sure you stop by a Guest Relations location & pick up a "Happy Birthday" button for him. I think that 6 is the perfect age for
The Pirates League at Magic Kingdom. Boys (& girls) are transformed into pirates & given their own pirate name. They learn to swash buckle & taught the official Pirate League Oath. At 4 p.m. daily, all Pirates who joined the crew that day are invited to meet at the stage in Adventureland (across from Pirates of the Caribbean) & participate in the Parade of Pirates. Packages are $29.95 + tax. Reservations are strongly recommended & can be made beginning 180 days prior to your trip by calling 407-WDW-CREW. MK theme park admission is also required.
You could also spend some one-on-one time w/ him at Downtown Disney. Cools things for him to do there including The Lego Store; Once Upon a Toy;
Characters in Flight ; customizing his own radio controlled vehicle at Ridemakerz & lunch at T-Rex Cafe (call 407-828-TREX to make reservations up to 180 days prior to your visit).
Click
here for a question I recently answered w/ other suggestions & please let me know if you need more. I know you're going to have an incredible trip filled with magical memories you'll treasure forever :-) Allison