how does the speech therapist treat jason?

Cynthia Lord's Rules follows a twelve-year-old girl named Catherine over her summer vacation as she takes care of her younger brother David, who has autism, and tries to make some new friends.
While Catherine at first puts her focus on trying to become friends with Kristi, her new neighbor, a real friendship blossoms with a boy named Jason Morehouse. Jason is a boy a little bit older than Catherine who cannot speak, and who uses a wheelchair. The two meet in the waiting room of the clinic where David goes to see his occupational therapist. Catherine sees that Jason has a big book of cards with words and illustrations on them, and that he communicates with others by pointing at cards inside the book. Catherine loves to draw, and over time she makes Jason a number of new cards that help him to better express himself.
The first day that they meet, Catherine sees an interaction between Jason and his speech therapist. The woman speaks to Jason as if he's a small child who can't understand her, using an extremely loud voice and exaggerated hand gestures, and dumbing down what she says to him. When she wants to ask a question, she asks Jason's mother, rather than just asking Jason. The next time Catherine sees Jason, he uses his cards to say that his therapist is a "Stupid. Speech. Woman." It's very clear that Jason's speech therapist essentially ignores Jason and his needs, and treats him as if he can't understand anything, even though he can understand what she and others say without any trouble.