My son was in two different therapeutic schools. He loved both. He did well. But my son was not acting out. He was well behaved for the most part.
I don't know how you contain him sufficiently to get him to a place where he could do a therapeutic school--without some sort of environmental containment. That is the thing.
A couple days ago when I was reading your posts I thought of Angela Lansbury the actress. I seem to remember that when her kids were teens both got on drugs. She packed them up and moved to Ireland!
It is not that residential is so great. But it cuts him off from his peers. He can't climb out the window. It cramps his style.
But the thing is, eventually these kids prevail. We have done every thing we can think of to pressure/steer/support my son. And the opposite. But eventually they prevail. They choose based upon their brain matter not ours. Like jrc writes: we can't alter the river.
I really like the idea of gentle nature.