My Son Has Legitimate Pain And A Reason For Narcotics

My son has legitimate pain and a reason for narcotics but his Dr. who has had him on them for a long time is now taking him off Percocet. Methadone helps his pain the most but his Dr. only gives him two per day and he is in and out of withdrawal . He is waiting for knee surgery. Would he be better off on
Suboxone and can he take it safely with Klonopin?