I am so sorry you are at this point, Donna.
If he cannot close his eyes, it is best to tape them closed gently using paper tape, at least at night, so they do not become too dry/dirty. I would also use eye drops frequently, either Genteal "moderate" or "severe" or Refresh Optive gel drops or his doc can write for something thicker if that helps.
I take it there is no other muscle that he can reliably move in lieu of a blink for communication?
Best,
Laurie