My daughter is wheelchair bound and uses a Trackchair for her hunting and fishing adventures, but it doesn't sound like your wife may need one for her mobility issues. A vacuum air actuator may be of use (beadaptive.com). The control box can be velcroed to the rifle stock so she can suck on the vacuum tube to fire the rifle when she is ready (takes away finger jerk or hand mobility issues out of the equation).
Let me know if I can help direct you in the direction of possible answers if you have questions. Each mobility issue is different so there are different ways to pull it off. I have to aim for my daughter and my wife has to help her with the safety and vacuum tube, while she watches all action on a tablet mounted in front of her; the scope mounted Tactacam sends the live view to the tablet no matter the angle or conditions where she can't turn to see. She's killed antelope, mule deer, elk, whitetail, aoudad, turkeys, and axis with rifle, crossbow, and shotgun, so we've worked out a system that works for her.
You'll come up with a system that works for her, and she'll have a great experience no matter what this fall. As I say for special needs hunters, the trophy is the experience.