LnL;
Sorry replying took a while -- holidays and sickness, you know.
I wouldn't be surprised if Stepdad were on the NPD spectrum, as it were. Excessive need for admiration, condescending/patronizing attitude towards DH, fantasy world of this story about SD11 where he's the "prince", beliefs that people are paying attention to him and not others, rules don't apply to him, vast sense of entitlement especially to DH's roles, lack of understanding of how damaging his behaviors are to the kids. Yup, at least in the ballpark.
What you're saying does make sense in terms of family systems -- that a family sort of "seeks" an equilibrium state, even if it's a dysfunctional one. The initial equilibrium at Mom's house has been disrupted -- which is good -- but this new equilibrium is showing up as Mom looking functional and Stepdad's behaviors ramping up. I think you're right that a lot of why Mom looks functional may be enabled by Stepdad somehow.
You hit the nail on the head:
He tries to control the environment and everyone in it as a logical management plan, without realizing he has the emotional maturity of a child, and is in no position to be in charge. To recognize his own emotional immaturity would destabilize the family, because then he would have to see that no one is in control, which creates too much uncertainty and anxiety
So... .this is just for some info, not to point fingers, because we all have our stuff to work on. But here's what the background is.
I can't remember if I've mentioned any of this here before, but Stepdad used to be DH's best friend. Back when Stepdad was married the first time (Mom is his 2nd marriage), they'd all hang out together. At some point after Stepdad divorced but DH was still with Mom, Mom told DH that she & Stepdad had feelings for each other, but nothing came of it then. This history is also how DH knew that Stepdad's dad left the family when Stepdad was teenage-ish. He was oldest son and stepped up to "rescue" his mom & siblings from "evil" dad leaving.
Circle back to DH & Mom having marriage troubles, which is after Stepdad is divorced. Stepdad has had a couple of sessions of MC from that, so they ask him to help them work out their issues (which DH admits was incredibly naive). Stepdad takes Mom's side but still tells DH that divorce was not a big deal.
Mom & DH separate, and 4 months later Stepdad is taking Mom out on a date. Divorce finalized a month or 2 after that, and then 3 months later Mom & Stepdad are engaged. They get married after being engaged for 2 months. This is not surprising to any of you at this point.
Their baby comes along 8 months later. Before this Mom starts calling Stepdad a "dad-style" "nickname". The kids don't call him this at first, but a year or so later (and up to now) it has stuck.
Then there are the hard years of SD11 saying stuff like "you're not my family" to DH. You guys can fill in all the blanks.
So basically it hasn't just been "oh, Mom married someone new, who is naive about stepparenting but will see how wrong some stuff can be". Mom married someone who is committed to believing that he's a hero who can replace his Dad/DH and rescue Moms With Kids. He is acting out this whole narrative where he is totally not his dad and what happened in his life is something he has heroically overcome. Basically his actions make it seem like he believes that DH is evil just like his dad and therefore "deserves" to be replaced. That's what we've been dealing with, along with all of Mom's shenanigans.
And you're right... .no easy answers. Until Stepdad chooses to see reality (and not live in an "emotional reality", as he has said), I think you and Counselor are correct, that this new equilibrium is where we're gonna be at for a while. It's so hard seeing how this effects especially SD11. She's at a point where she's just not ready to see any weaknesses in his armor. In a way, she might have unmeshed with Mom some, but she enmeshed with Stepdad more -- like, if he's flawed, then his narrative about her being a great hero would also be flawed, so she wouldn't be great.
And yeah, she has a ton of anxiety and is not sleeping well. Plus does the "keep it in/let it all out" dichotomy. Maybe it's both par for the course at 11, but amplified b/c of family dynamics?