In our case, I requested that my mom's neurologist send a doctor's request to the DMV to have a behind-the-wheel evaluation. Mom received an official DMV notice in the mail and she asked if I could help her get to the special facility where the test was to take place. Because I felt sure that she should not continue to drive, I told her that she would have to take care of the details herself and that I was unable to help her. She was upset but she attempted to get there herself. She got lost on her way there and missed the appointment. All other appointments were overlooked and her licensed expired. At that point, thankfully, she was fairly compliant about losing her freedom to drive and we didn't have wars about her driving. Because we lived together she didn't seem to mind me driving her if we needed to go somewhere.
I understand that others have a much more difficult time relinquishing their freedom, but in this case, I think it helped may have helped my mom to know that "officials" (in this case, doctors or the DMV) were the ones who helped confront the issue of driving.