GBS communication while on ventilator

My father in law is in ICU with what they are pretty sure is GBS. We are still awaiting spinal tap results. He is currently on a ventilator and partially sedated. Does anyone have any tips for helping to communicate with him? He wakes up from resting startled and anxious. Thanks.

When I was intubated, the nurses and my wife used an alphabet tablet. The tablet had all the alphabets from A to Z. My wife would scroll with her fingers across the letters and I would blink if or nod my head to indicate the letter I wanted to use to spell out the word. Worked well. Also my wife had flash cards with words that I used a lot. Hope this helps.