I had been nurse to a little boy who was deaf and unable to speak or use his hands to communicate. Other than discovering a fever or observing a runny nose, we were unable to ascertain when he had pain or was sick.
Something about the repetition of "Bear still felt sick!" created an understandable connection for him, so that we were able to ask him if he felt "sick" or "pain", like Bear. Karma Wilson's excellent book, including the twist that made him laugh, and the empathetic ending, provided a breakthrough for us.