Hi Lisa!
Thank you for bringing your question to the Disney Parks Moms Panel!
Happy Birthday to your grandson! What a fun way to celebrate. You'll actually be visiting on MY birthday so have fun for me, too! Make sure to ask a Cast Member where you can pick up a Birthday Button for him. He may not want to wear it, but it will make a great keepsake for his special year.
Most of the table-service (sit down) restaurants at
Walt Disney World Resort would be able to grant your request for whole milk. The quick-service locations (where you walk up to order) may not always have it, but will be able to point you somewhere that does.
My suggestion is to find it at the coffee locations. Generally, they will be able to give you whichever milk you prefer and can put it in a cup for you. There is a
Starbucks location in each park, as well as other coffee kiosks. You can find coffee service locations on the park maps when you walk in.
I hope this helps! Please let me know if you have any other questions.
~Lori