The physician can report patients as a concerned citizen. The patient may then be requested to re-apply for license. The patient will then be asked if they have seizures. The legal onus is on the patient, not physician. In Texas, the DPS and Dept.
Health have a physician referral form.
A physician who is licensed to practice medicine in Texas may voluntarily inform the department or the board, orally or in writing, of the full name, date of birth, and address of a patient over the age of 15 years whom he or she has diagnosed as having a disorder or disability specified in the rules of the department. The release of such information by the physician to the board is an exception to the patient-physician privilege requirements of Section 5.08 of the Medical Practices Act. In all states, physicians should inform patients of the law. Incorrigible Physicians Physician CAN NOT tell the patient whether they can drive, that is the State's function. You've put yourself in an untenable legal situation unnecessarily.