Dr Hahn, to your question, I'll give an answer that I admit is anecdotal: I have been at a residential trauma treatment facility for 21/2 years now and I would say that effective trauma treatment requires: First - create a sense of safety in the therapeutic environment. Second - connection, a peer group with similar challenges is needed, a therapeutic community. Third- trauma and grief specific therapy (SE, EMDR, CPT, etc). Fourth- access to professional support on demand to assist patients with processing.
I have seen good results with fairly resilient people in outpatient treatment that offers aspects of this, as well.