Replied by Lisa (Thousand Oaks, Ca, Usa) on 11/23/2012
Hi Charlotte, You don't mention anything about his diet or his digestion. Since you say he has no dental issues, the next thing I'd look to are these two things. According to my traditional Chinese medicine Dr. this is due to poor digestion. Also, an oily tongue is an indication of dampness or phlegm condition (retention of food).
The tongue is very important in diagnosing in TCM. You may want to consider seeing a Traditional Chinese medicine Dr. who would be able to address this issue easily. If you want, google: tongue in Chinese medicine to learn more.
Hope this info helps you and your husband. Lisa