Dating a former patient
Besides the ethical dilemma, there are issues with the quality of care…
The phrase "patient education" refers to a doctor informing a patient about their sickness, disease, medications, and more.
The doctor - patient relationship is protected except in cases where abuse is involved. If you want to develop a relationship with your doctor (and he agrees), then you would change doctors immediately.
If you aren't his patient and you strongly feel he's interested in you ask him out for drinks.