That sounds like aphantasia.
Until maybe 10 years ago, I thought that was some exceptionally rare condition, and that I'd be instantly able to tell who had that by how they acted because that person would be so weird or different than everyone else.
Turns out lots of people have it, including my mother.
It was so weird to me, because I have an inner monologue and it's pretty much always going. And I can "hear" it inside my mind. I can visualize anything I can think about, even watch "movies" with a "soundtrack" in my own mind. It's so omnipresent in my life, and that's just not how everyone's brain can work.
And of course, people who don't have that in their mind are no less intelligent or anything. Maybe it's easier for them to focus than it is for me! Lol
But when I first heard about it, I wondered things like, "How can they read?" or "How can they know what something looks like from a description, or how can they understand how something would be moved in a 3D space without actually moving it?" Lol