This was really good. I liked how you managed to give Echo the tone and feeling of a 5 year old. The clarity and the intuitive knowledge of emotions kids often have shone through very nicely.
“You’re always working,” Echo said, her eyebrows scrunching together. “You should have fun, too. Painting is fun. You should paint,” Echo declared sagely, holding Claire’s eyes as she made her diagnosis.

And I liked how you let it shine through that there is a little more going on beneath the obvious.
“I have to go now,” Echo said looking over at Claire, her eyes holding the doctor’s for a moment as if there was something more she wanted to say, but was holding herself back because of Tanner’s presence.