I have a friend whose husband is having some serious health care issued and she is fearful of driving on her own with them to other cities in Texas for medical treatment as she is not able to handle any problems that may come up especially with the vehicle.
If he is going to Texas Medical Center in Houston (UTHSC, Baylor, MDAnderson)
each hospital has social services that can get you in touch with resources. TMC is primarily folks coming in from outside of Houston so this is nothing new to them. She also should belong to AAA premium for car issues - about $ 100 a yr.
website: msmedicaltransportation/patient_services.html
Another way to handle this is to hire a caregiver from an in-home caregiving agency and explain that she needs someone who can drive her and her husband in the caregiver's vehicle and spend the night away from home at times. There are many caregivers who do this and it would be a way of not only having transportation but having caregiver assistance with the husband. Of course, your friend would have to pick up the caregiver's mileage as well as hotel and food expenses. Still, this would be worth it to have that extra person there to help with her husband.