How do you know someone isn’t making it up??

So, an attention-starved person in my family

(examples of “attention starved”: exaggerating injuries, self diagnosing mental and medical issues for attention, constantly copying other people’s stories and opinions to be liked, pick-me pro Trump vibes in front of men, progressive “girls-girl” in front of women)

has been claiming to have aphantasia for the past ~6 months. Here’s the thing. I’ve known this person their entire life and there has never been even an INKLING of anything to suggest that they might have this condition.

This person has been an avid reader our entire upbringing, was always imaginative and theatrical, etc. There has NEVER been anything to suggest or even elude to this condition until a few months ago. Now they’re trying to say they have rarely ever, dreamed because they can’t see anything. Why wouldn’t we have heard about this before?

This person is the most chronic liar (about dumb and unnecessary things) I know, but maybe I’m being the jerk and there is such a thing as late-onset aphantasia??

How can you tell if someone actually has it or if they’re just making it up??

For the record, I find this condition to be really fascinating, I’m not denying its existence, and I don’t mean any disrespect to anyone who has it!