I agree with the other posters, but I wanted to respond to one comment.
Most of the people who write about wheelchair/
ECV abuse are writing what they
think about
assumptions they have made, rather than about actual facts.
Many people assume that guests using wheelchairs or
ECVs get to bypass lines on most attractions. Because of that, they
assume that anyone they see who does not
look like they
need the wheelchair or ECV
must be abusing it to get what
they think is an advantage.
When MK and Epcot were built, no one thought that much about how people using wheelchairs or ECVs would access the attractions. As a result, some were not wheelchair/ECV accessible or were not accessible thru the regular line; those attractions had a 'wheelchair entrance'. People who didn't use wheelchairs or ECVs saw the 'wheelchair entrances' as a 'perk' or something Disney did to be 'nice' to people with disabilities.
Those of us who used wheelchairs or ECVs knew the truth; that was the only way that those particular attractions were accessible. As time went on and those attractions were renovated or replaced, some were able to be made accessible without a wheelchair entrance.
AK and the Studio were built with accessible lines/attractions (called Mainstream Access), so in most cases, people using wheelchairs or ECVs at those parks will wait in the same lines and for the same amount of time as other guests (LONGER in some cases).
The majority of attractions at WDW are Mainstream Access, so don't worry about people thinking your mother is 'abusing the system'. As the other posters wrote, if she can't walk the distances, she needs to use something.