This is such a hard transition. I recall when this happened with my dad in his eighties. There, it was after going through a health-related issue that the hospital notified the DMV-equivalent, and they acted. Still, it was a very hard thing for him to go through. We found a service that provided on-call drivers for the elderly. The driver would arrive on a scooter and drive my parents in their own car. Soon, they developed a relationship with tge driver and it became a regular part of their routine.