Does your friend need to scooter for long distances or does she need it all the time in a cabin?
I traveled with my mom who used a scooter. We booked a regular sky suite for us several times. She got in the shower 1-2 times during the cruise and only when docked in port. The tub is VERY hard to get in and out of. She sponge bathed the rest of the time and got her hair done at the salon. The tub is REALLY hard to get in and out of. We found the size of the sky suite was perfect to park the scooter and charge it since my mom could ambulate with her 4 prong cane when in cabin. Mom needed the scooter for distance.
When I traveled with my mom and sister (who has MS), we booked a royal suite for the walk in shower (celebrity provided a shower chair) and the second bathroom where we had the over the toilet raised chair because my sister needed handles to get off/on toilet. Plus we needed the extra room for 2 scooters--- one for my mom and one for my sister. During this last trip, my mom was on oxygen 24/7. We worked with celebrity to ensure the oxygen concentrator was there with a humidifier, the bath bench and toilet seat. Mom had a portable oxygen unit but we needed a concentrator in cabin. This trip was alot of work to make happen. So glad we did it as was my mom's last cruise and my sister can no longer cruise due to dizziness. The memories are priceless.
Best story was when we ate at Lawn Club Grill. When we were done eating, two of the crew went to get the scooters for my mom and sister. They decided to have some fun and were racing each other around the deck and as they kept passing us they would wave and keep riding...it was on of the funniest things ever. This memory will with us forever.
Lastly, my husband and i have traveled in a celebrity suite many times. I agree with what the others have said. If she needs the scooter in the cabin and near the bed, it is too tight in the bedroom to make that work.