Hello Lisa and thanks for bringing your question to the Disney Parks Moms Panel.
I'm so sorry to know your dear son has injured his right wrist resulting in the need to a wear a cast and also what dastardly awful timing to coincide with your visit to Walt Disney World Resort!
I would say in the first instance and certainly while your son is still recovering from his injury it would be a good idea to check with your own family Doctor to get their recommendations for your son's well-being and safety during his trip to Walt Disney World Resort.
I'm sure you will find many Attractions at Walt Disney World Resort for your son to enjoy whilst wearing his cast and perhaps a visit to
Guest Services at each Disney Theme Park entrance to ask for guidance would be a great initial port of call.
All Cast Members at Walt Disney World Resort are simply
Wild About Safety and will always put the best interests and safety of Guests first.
A small bonus of wearing a cast might be that your dear son gains a lot of extra fuss and attention from Cast Members and Disney Characters; I'm thinking everyone will be keen to know how did it happen? Perhaps during a sword fight with Captain Hook or maybe when bravely fending off a bear like Mor'du?
If I can help sprinkle a little extra pixie dust over your upcoming trip to Walt Disney World Resort please pop back to ask me another question.
Have a great Disney day.
~ Jane