YES, there are 2 things he can take. Fenugreek capsules, as many as 12 a day and also Antronex from Standard Process in the US, you can call them at 800-558-8740 and ask them for a doctor in your area who carries their professional line of whole food supplements. Fenugreek will divert the mucous production from the sinus and chest down into the intestines for elimination. The antronex acts as a natural anti-histamine and also helps to dry up mucous. I know of two singers that take this protocol because the mucous interfered with the voice and it has improved them by 80-90% they both say. Hope that helps :)