Thalia does make a pretty good metaphor for this. It makes sense that Thalia would age, because the tree is living, and it grows and ages, so she aged at a tree's pace. But gold doesn't age, so, in theory, time could pass without Midas's victims aging either.

Thalia does make a pretty good metaphor for this. It makes sense that Thalia would age, because the tree is living, and it grows and ages, so she aged at a tree's pace. But gold doesn't age, so, in theory, time could pass without Midas's victims aging either. I'm not sure about dreaming. I think Thalia visited Percy's dream in lightning thief, while she was still a tree, but tree dreaming rules might be different. I don't remember what Piper was dreaming about, but it might be important to answering this.