One Of My Clients Is Complaining Of Pain In His

One of my clients is complaining of pain in his tongue. Usually has some neuropathy due to a previous stroke. However Orajel and some Tylenol helps but not today. He is moaning continually about his tongue. We noted that the center of his tongue is black and the rest is white and somewhat "gunky". Is there any direction I can give to his daughter. Should she call the doctor right away or he had a mouth rinse when he had thrush a few months ago and she still has some of this to use?