Hi @Hank,
I agree with what @Former-Member has said. I think your daughter's therapy has been working as she is now weight-restored. But once we get treatment for our issues, it brings them into clearer focus and we can no longer hide from them.
I think a lot of people have the feeling that 'therapy is not working' because therapy often brings painful emotions to the surface where we can deal with them. Then it feels like we will always be in pain and that our issues will always torment us.... but this is actually not the case- what happens is we begin to deal with our painful emotions and we gradually move forward. In can be a very gradual forward movement- with many small set-backs, that can feel overwhelming at the time.
Being around your daughter 24/7 would be a huge strain for any teenager- parent relationship.... even if the teeneager didn't have an ED. With you doctor's permission, can you allow your daughter to go out on the weekends with her old friends? Movies, beach, picnics, whatever? That way she has time to be a 'normal' teenager.
Can she recommence going to school or look at doing a course?
If she has a particular issue with one of her therapists/doctors, then it would be good if you could encourage her to talk about it. These things can be resolved. Your daughter might respond better to a psychologist who is close to her own age, for example.
I'm sorry to say I am not a parent, so I guess I can't imagine what your situation would be like... I did have a mild ED when I was a teenager which went untreated, in spite of multiple threats from my parents! I believe my ED was related to my anxiety. I more or less out-grew the ED tendancies by the time I was 18.