Steph--you know I love you, right? I have some stuff to say and I hope you will hear it the right way. I know that you do such an AWESOME job with your kids...the way you manage all of the medical stuff--truly great.
But with Nate, here's the thing. A few pages back you posted that you hate being a step-mother. I almost posted this then, but I let it go. But clearly you are still having a hard time with that issue, so I thought this might help.
If you feel that way--that you hate being a step-parent--then Nate is definitely picking up on that. And if he is picking up on that, then it is no wonder he doesn't say two words, right? I mean, who is comfortable going into hostile territory? (not to mention that teen-aged boys aren't particularly verbose anyway.

)
I am with you on the manners thing, sure...that is the bare minimum, but I am sure he is picking up on how you feel.
And look at it this way...he didn't ASK to be born into this. He didn't ask for his parents to split up when he was very young. He didn't ask for his dad to get married and start a whole new family with new kids. No one consulted him about these massive changes in his young life. As a kid, it totally sucks to see your parent start over with new kids...kids who get to live with that parent 24/7 and you are left out only seeing the parent when it is convenient.
Now, absolutely none of that is YOUR fault at all. Please don't think that is what I am saying. I am just trying to point out his perspective.
And as a parent, YES, Steve (and sorry, I have to spell it that way or I get all confused!) Steve SHOULD be putting his kid first. Don't you put your kids first? Of course you do. Because you are a good mom. He is trying to do what he can to be a good dad to this kid that he doesn't get to be with every day like he does the other 3.
And here is your part to play--YES, Nate gets to be there as much and for as long as he wants. (You made a comment about that a while back. Like, does he just get to be with you on every holiday. YES, he does.) It is his father's house. And you knew that Steve had a son when you married him. You went into this with your eyes open. So now you have to open your home to Nate without hesitation, without negativity, and even without rolling your eyes!
I know, KNOW, that you are doing a great job. You juggle work, family, ww, a hellish schedule, a new house...all of it. And it is so easy to get frustrated by the things over which we have no control. But this...this is something you need to accept. Accept it and move forward and you will all be happier and breathe easier with the situation.
Ok, off my soapbox.