I've been praying for your family several times every day labgrade. I'll keep it up. I hope things stabilize and all works out, the alternative isn't acceptable. I know the constant up and down with recovery followed by setbacks can be very difficult. Are his wife and mother in contact with a counselor and/or clergy for spiritual and or mental support? I know you are doing what you can for them but sometimes someone outside is better. From the sounds of it you are seeing yourself as something of an outsider, yet from the tone of your posts it is clear that you really love your step-son (more like your son from how you clearly feel about him). Don't deprive yourself of the right to feel about this. Are YOU in contact with a counselor or clergy outside of THR for support? I can tell the support here, especially from certain members, means a lot to you, but are you speaking to anyone professional from outside who can bring another angle for you?
Anyway, don't ever lose hope. We are all praying and hoping for you, Shane and your family. Stay strong but don't be afraid to allow yourself to feel, to cry, scream or whatever you need- he is your son (step or not) and it is clear how much you love him.