"If a plan covers children, they can be added to or kept on a parent's health insurance policy until they turn 26 years old.
Children can join or remain on a parent's plan even if they are:
Not living with their parents
Not financially dependent on their parents
Eligible to enroll in their employer's plan
These rules apply to both job-based plans and individual plans bought inside or outside the Marketplace."
This is from "healthcare.gov" and they are clearly considered children until age 26. Even if they are married, not living with their parent's, and not even financially dependent on their parents.