Doctors and their patients are a fertile topic, especially when the doctor has a penis the size of a good bat, and the patient looks like she just stepped off the modeling catwalk. Their imagination is also fine, they do not limit themselves in their desires. However, both clearly have not had good sex in a long time, so they greedily pounce on each other. But now they will definitely have something to remember!
I have repeatedly advocated this kind of close family ties. It is better to have granddaughter at home, and grandfather to have some fun and share the experience, than to go back and forth with someone I do not know.