R.F.
T.,
First of all: YOU HAVE NOT FAILED AS A PARENT!!! You and your husband are trying to deal with a series of serious problems as best as you can. However, your son's world is no longer the world he knew. He's moved. He's changed schools. He has a new step-father AND a new baby brother. He's had to share you with this new family. He's absolutely lost! I would strongly urge you to consider counseling for him. He needs a place where he feels safe to vent and rage about all the changes that's happened to him without his control. The changes that happened to him are in no way "wrong". They are, however, out of his control and he's just spinning and needs to find some solid ground. He needs to find help in coming to terms with so many changes in such a short time. He apparently doesn't want to hurt you so he just doesn't say anything. Hence, the "no" when you ask him things. He sounds like a really great kid who just needs a little professional help to guide him back to where he needs to be.
Good luck and best wishes for your new family,
R.