I agree with Mark that you should look at the Volvos. The new XC90 is impressive--you'll find my review linked beneath its photo. My main concerns with it: price (which might not be an issue at all for you) and unknown reliability, since it's all-new.
As Mark notes, Volvo has an all-new S90 large sedan on the way, if you find you like the new XC90 but would prefer a sedan.
That said, I've been very impressed with the 2015-2016 Hyundai Genesis sedan. It's an outstanding car all-around, especially for what it costs, has very comfortable seats, has excellent safety ratings, is available with a full array of safety features, and has been very reliable so far. On top of all of this, they haven't been selling well because the badge lacks prestige, so it should be possible to get a great deal on one.
The main negatives with the Genesis: no prestigious badge, non-luxury dealer service, and in-town fuel economy that isn't as good as an Audi or BMW with a turbocharged four-cylinder engine. (The Hyundai has a big V6.) But you really should drive one before dismissing it.
Whatever you seriously consider buying, I'd ask the dealer to take it home first for a day or two to make sure that the seats are comfortable for her. It is very hard to properly evaluate seat comfort during a dealer test drive.