Are night sweats caused by drinking alcohol a sign of a serious health risk condition?

Many causes. There are many reasons for night sweats and drinking alcohol is not one of the common causes. Infections, (including tb), cancers, hormone problems, and gastric reflux, or cardiac problems can all lead infections. So night sweats themselves can be a serious health situation. You should probably see a medical professional to have an evaluation.
Yes. It is a sign that you have become dependent on alcohol. Increased sweating, along with anxiety, insomnia, tremor, all occur as we get progressively more dependent on the drug alcohol. If you are having sweats at night, you need to discuss this with your doctor. A medical detoxification may be necessary, together with a good counseling program to explore why you drink and best ways to stop.