Doctor fathers

My son James was arguing with his cousin about whether or not your brains can leak out through your ears:

Cousin: My dad knows all about the human body, he's a doctor.

James: Well my dad is a writing doctor.

Cousin: Some doctors are scientists or explorers, they help people. Surgeons help people too, and children's doctors.

James: My dad is a doctor in writing. He helps people with [long pause] – ah, somethings.