With some catastrophe in his background, he arrives on a hot frontier world (requiring a survival suit?) populated by humans, to live with a kind, morally strong woman, who perhaps owns a bar (... or spacecraft repair shop? I forget).
The kick is that his people cannot choose who they mimic, and do so unconsciously. E.g., his shuttle was late and the woman's feet have become burnt through her boots from waiting for it; he doesn't realize he is copying her pained way of walking until someone rebukes him for it.
The tension ratchets up as the boy realizes there is a really nasty fellow populating their frontier community. And a blind girl. And he thinks he has begun to mimic someone but he can't yet tell who.