Of Sound Mind is an fine portrayal of the ambiguities of being a hearing child of deaf parents and of a young man forced to act as a adult early in his life. It explores the themes of responsibility and independence. While Dad's initial stroke is key to the story (and even telegraphed in the book blurb), I can't help but trying to find resolutions to the story without Thomas's death. Somehow his Father's death seemed gratuitous and not to add a lot to the story. This difficulty with the ending is why I only rated the book as 3 stars.
While Jean Ferris consciously made the decision to translate the signed conversations into conventional written English, I wonder how much additional insight could have been gained by following the ASL syntax and word choice more closely.