All of the parks offer things to see from the car. A few years ago we visited Zion & Bryce while I was still recuperating from an accident. I enjoyed just being out of the house.
As for Zion, the shuttles are still going until the end of the month, so bear that in mind. Use of private cars in the main canyon is restricted. The drive up the main canyon is beautiful with many pull outs. As is the case with most areas, the best photo spots take a little walking, but there is still plenty to see from the road. A beautiful but seldom visited part of the park is along I-15 at mile marker 40. The Kolob Canyon area has a short five mile drive that is spectacular for those who are confined. Another drive starts at the town of Virgin and goes to Kolob Terrace area. This is another beautiful drive for those who have trouble getting around.
The Bryce Canyon road is on top of a plateau. The view points are all above with you looking down into the canyon. Most of these areas are wheel chair accessible, but to really experience Bryce you have to walk down into the canyon. If you have never been there, howeve, I would definitely make the trip. Sunrise makes the rock glow.
Most people go to the Island in the Sky district of Canyonlands. Like Bryce, they stay on top of the Mesa and look at the vistas below. As glorius as they are, and believe me, they are! you really have to get a jeep and drive some of the many 4x4 roads to get the feel for the park. Still there are many areas that you are able to see from the parking lots (Mesa Arch is not, although it is a short walk). The Needles district is an hour or so south and is just as amazing as the more visited portion of the park. Newspaper Rock is next to the road and much of the beauty of the area can be seen from a car, but again, this is a hikers paradise. The Maze is for dedicated outdoor enthusiasts and is seldom visited. While at Canyonlands, don't miss Dead Horse Point, which is great for those in wheelchairs.
Arches is much the same, many great views from the car and parking lots, but most of the arches require a walk. Delicate and Landscape arch can't be seen unless you are able to hike, while the windows section and Balancing Rock are next to the road.
The North Rim of the Grand Canyon has many areas that are wheelchair accessible, but it is closed as soon as the snow flies, which is about this time of year. You'll want to check before you go there.
Hope you and your wife enjoy the area as much as I do. Great time to visit the parks.