People cutting in front of the person in the ECV is one of the worst, I can tell you that from experience. I'll be walking along and getting lost in my Disney happiness bubble, turn to say something to mom and she's not there. Then I stop and she's about 4 steps behind from people cutting in front of her as she's rolling along.
If your friend is able to walk a little, that will be a great help in the pirates queue, but there are wheelchairs you can borrow to go through the queue and there is an elevator just after you exit the boats at the end. There's also an elevator in the queue for Dinosaur, and the ride CMs are really good about explaining where to go and what may be expected in other queues, like when you get to a certain point in Toy Story Midway Mania, you'll be directed to go a different direction in the line to the wheelchair and ecv load queue.