Hi Stephanie.
How exciting that you're planning to surprise your mom with a trip to Walt Disney World!
Personal size, soft-sided coolers, required for safe medication storage and administration, are certainly allowed to accompany your mother into the parks with you. At the Bag Check point where you enter the parks, simply advise the Cast Member checking your belongings that your mother is diabetic and is carrying syringes and refrigerated insulin with her. I've included a link to a related '
Frequently Asked Question' regarding the carriage of medications into the parks.
You'll find sharps containers secured to restroom walls for safe disposal of her syringes or sharps, if necessary.
I hope this information helps with your plans Stephanie.
If you have additional questions, please don't hesitate to write me back. It would be my pleasure to assist you further in any way that I may!
Wishing you a simply Magical time at Walt Disney World!
Kirsten