WF, my son J was in a private school last year. Halfway through the school year, he completely shut down, was very depressed and wasn't doing any schoolwork. We had him admitted to a day treatment program at a local psychiatric hospital, where his medications were straightened out. However, when he went back to school, he was still socially withdrawn and not doing his work. The private school did not renew his contract for this school year.
Last summer, we went through the IEP process with our large county SD. J was placed in a self-contained ED program for socially and emotionally fragile high schoolers. For a variety of reasons, one of which is that he doesn't really fit the profile of the rest of the kids there, the program is not working out. He has made no friends, has no connections to the adults in the program and is still not doing his work. He is also not talking at all when he sees his psychiatrist, who in addition to medication management, does weekly psychotherapy with J. However, his mood at home is very good, he's compliant about the few chores we ask of him, and he has a good relationship with both his dad and me.
We're telling the Residential Treatment Center (RTC) staff exactly what's going on -- our son is therapy-resistant (but medically stable), socially withdrawn and academically underachieving. While the RTCs we're looking into have psychiatrists on staff for medication management, the main focus is therapeutic -- getting these kids to look inside themselves and to learn coping skills to confront their challenges. The length of stay is typically 6 to 9 months. Most strongly recommend a wilderness program beforehand to break down the resistance so the student is ready to access the therapeutic process. I won't lie to you -- these programs are expensive, but we plan to take out a loan.
If you're interested in knowing the programs we're considering, I'm happy to PM them to you.