A person on a ventilator can read and point. The ICU and Ventilated mode is live: its own library, ICU & Breathing Tube and After Surgery, holds short phrases for breathing and the tube, calling the nurse, pain from 0 to 10 and where it hurts, yes and no, comfort, what's happening, family and everyday needs. Choose the mode in the guided setup and those phrases open first in the Phrase Library and at the top of the Communicate page; the Medical Words dictionary and the emergency phrases work from a hospital bed too.
The condition page on the public site tells the full story and ends with the way to create an account.