I'm so sorry that you've been through so much pain and fear, tbone. It really doesn't sound like your son should come home just because his time in Residential Treatment Center (RTC) is up. Do you have other children at home? You mentioned a daughter ... is she a minor? You would have a very strong case, in terms of filing for a CHINS or an incorrigibility order, for protecting other minor children. In your other post (Conduct Disorders thread, which I got email notification for just before I had to go out earlier today) you mention that YOU went to jail after your son tried to choke you ...!! Clearly your son is very manipulative and I can see why you're afraid of him.
The Residential Treatment Center (RTC) should be into discharge planning for your son about now ... maybe get in touch with them and tell them he is not welcome at home, give the reasons, and try to work with them on options. If nothing else, they should be seriously questioning his readiness for discharge if he's OD'd three times with them! If necessary you could say that you don't believe you can keep him safe (which is the truth) at home given his recent ODs. It doesn't sound as if your son is ready to turn things around, so you have to protect yourself and your family. Best of luck, and keep posting. We'll be here.