Or what would that be called?
For example, not believing someone about their health issue, refusing to believe that it impacts their ability to function or can be a valid excuse for things, often solely on the basis that it’s not a recognised disability, and/or claiming that their opinions can’t be taken seriously due to their health problem?
Definitely assholery but perhaps not discrimination in a legal sense - but that will be heavily dependent on wherever you are and possibly not answerable outside of court.