This is hard to do. They are out there, but look to more mental illness type in-patient treatment centers, as the vast, vast majority of chemical dependency type inpatient centers will only detox people on buprenorphine (at best) and will probably (at best) try to get him from methadone to buprenorphine in order to get him into their program and make some money off him. Too bad you don't live in LA, I could have actually help you out on this. I wonder if some place as "forward thinking" as Hazleton would allow for someone inpatient to detox on methadone, I kinda doubt it.
Why is it that he isn't trying to taper down on his methadone by himself, and then if treatment is required just go inpatient for thirty days once he has jumped off of 0mg? Even a medically supervised detox off methadone is going to be a lot less comfortable than a slow, steady taper off methadone without much in the way of comfort meds. It takes a lot longer, but it is infinitely less expensive. Yes, it is less structured, but get him involved in an out patient program in the mean time, or at least get him going to some kind of support group that is okay with his being on methadone (or that he is comfortable with, as lots of people I know are on methadone and in NA and just don't say anything about their methadone, and they get on fine, if that's your cup of tea I mean).