Stephanie, I have many friends online that have had radiation to the mouth/throat area. Mucus is the biggy, and unfortunately it seems to be a permanent fixture for most folks. Does he have a suction machine to suction out the mucus? If the mucus isn't removed, it can turn into a lung infection. Because of trapped mucus, I was on antibiotics for over one year before getting the tracheotomy. I hope things bet better for you!