My Da Is 88 Years Old And Has Trigeminal Neuralgia

my da is 88 years old and has trigeminal neuralgia from shingles on his face that started sept 1st. he is in tremendous pain with no relief. on gabapentin (neuronton ) and oxycotin.., nothing is helping him. The pain management dr just prescribed fentanol patch to use along with these drugs and Tylenol I am petrified it will kill him.. its stronger than heroin and highly addictive.. please give me some help