Will you have your own wheelchair, or will you be getting one at the park?
If you have your own wheelchair, and if it folds down small enough to fit in the trunk of a car, I would think you could Uber between Wilderness Lodge and the Beach Club. Then use the International Gateway Entrance to Epcot, and you would be fairly close to France.
If you don't have your own wheelchair, and will be renting one at the park, you need to think about how far Mom would have to walk: between bus and wheelchair pick up at the front of Epcot if you take the bus. Also, you would need to find out if you can rent wheelchairs at the International Gateway entrance. If you can, Mom would be walking between Beach Club and International Gateway.
You might want to change the title of your thread to include the word "wheelchair." Otherwise people might think, "I'm not going to bother replying to yet another general Uber thread."