I never heard of using methadone to deal with a klonopin addiction. I've only heard of using it for opiate addictions or for chronic pain. Klonopin is NOT an narcotic. It is not a narcotic. Is he using something else?
I'd focus on me and the baby and let him take care of himself. You cannot save him. Just my opinion, but it sounds like a crock. He needs to talk to a doctor. Not "some folks" who aren't doctors.
Educate yourself my dear and don't listen to his words. It's his actions that count. To me it sounds like trading one addiction for another.