Welcome Aboard, Kasia!
Thanks for stopping by the Moms Panel with your question.
I'd hate to hear that any guests would need to cancel their Disney Cruise vacation, but I know sometimes it happens due to unforeseen circumstances.
Since cancellation fees vary, depending on sail dates, locations of departure and arrival ports, and certain stateroom categories, I recommend you refer to
Disney Cruise Line's cancellation policy located on Disney Cruise Line's official website.
If you have questions regarding a specific reservation, I encourage you to call Disney Cruise Line directly at 1-800-951-3532, and have your reservation number handy when you call. A Disney Cruise agent would be able to assist you with any questions you might have.
I hope this helps! - Diane W.