Being that the original post is 5 plus months old I doubt the OP'er is checking but here is my response......
I know it is far from a sports sedan but I would recommend your Mother try to get in and out of anything that you are considering, it will be eye opening. I am in the exact same boat and decided to buy as a DD a Honda Odyssey Minivan. Nowhere near my first choice for fun but it is an incredibly useful / practical vehicle for day in and day out driving. I honestly really missed the past minivans that we had when the wife was driving them before all of the kids started driving, she now has a SUV after ~ 15 years of driving minivans. 23 city mpg and over 30 mpg highway, TONS of room inside and comfortable as all get out to run 80 plus on long trips. My wonderful Mid 80's Mother and her friends can get in and out (for casino trips) with ease.
Like I said have your mother try to get in and out of various "Sport Sedans" repeatedly. I doubt anything (depending on their mobility) will be a good fit.
Good Luck.......Mark.......
