I am not a doctor, not even on day time shows, but I believe a thick film on the tongue, on a regular basis, has to have a good reason and it is not normal to have. Nor would it just go away with scraper. It may for a short time, like a session , but you may prompt a brushing, scraping prelude next time with both participating.
Just ask him if he had shit for lunch. He may surprise you and say no just DATO'd that piece of shit wife of mine.