Hello, Diane!
I understand your father's concerns. My mother also uses a scooter, and we have found that she can relax and enjoy! Most of the attraction queues are ECV friendly, so your father can use his ECV to access the queue right up until the loading area. Cast Members will direct him on loading procedures for each attraction, as it can differ from attraction to attraction. In most cases, he will only have to walk only a few feet before entering the vehicle.
Your father may also find comfort in knowing that there are access categories for Guests with mobility concerns. Some attractions will allow him to remain in his ECV while others will require him to transfer. Attractions such as Jungle Cruise or The Great Movie Ride allow him to enjoy the experience right from his ECV. There are designated viewing areas for Guests (and their families) for shows like Fantasmic! or Festival of the Lion King.
Keep in mind that there are few places, due to the queue design or limited loading space, where an ECV must be parked outside of the attraction. Your father must transfer to a wheelchair before entering the queue. For example, the queue at Buzz Lightyear's Space Ranger Spin does not accommodate all styles of ECVs, so there are wheelchairs available so he can access the queue. My mom finds it difficult to transfer into a boat at "it's a small world", so she chooses to use a wheelchair that can be wheeled right onto the boat. You can find a list of experiences for each access categories on the
Services for Guests with Mobility Disabilities page.
I hope this helps to reassure your father that a magical visit awaits and your family can focus on making magical memories together! Please let me know if you have other questions as you plan your vacation.
Missy