Part 1: Who is considered disabled in the United States?
Per the Americans With Disabilities Act (ADA)— a person with “a physical or mental impairment that substantially limits one or more major life activities, a person who has a history or record of such an impairment, or a person who is perceived by others as having such an impairment.”
Part 2: What are some major life activities per the ADA?
Some of them: caring for oneself, performing manual tasks, seeing, hearing, eating, sleeping, walking, standing, lifting, bending, speaking, breathing, learning, reading, concentrating, thinking, communicating, and working.
Part 3: A disabled person can nave a non-apparent disability.
For example, diabetes. And yes, diabetes is considered a disability, at least in the US.https://www.diabetes.org/tools-support/know-your-rights/discrimination/is-diabetes-a-disability
Part 4: A disabled person can have a dynamic disability, that manifests in certain periods.
Example: A PTSD survivor might experience flashbacks that change the way the body functions for a period of time. During that time, the survivor might need a safe space to process the flashback.