He seems to have hyperphantasia, judging by every example of mental images he described. It's not a requirement, as the example from the other person on the beach didn't need it to feel that level of self-feeding joy.

But I wonder if aphantastic people have a harder time with this? Or maybe easier with less mental distractions?

I have aphantasia, and I can definitely get deep into music

and to be honest, for me, turning great music into a mental movie seems to be almost missing the point, I prefer experiencing it as music

I think aphantastic people would be able to but using an inner monologue/internal text? Or even just the feeling and concentration on that feeling?

Tangentially trying to imagine not being able to visualize mental images is really hard.