You have an order of protection, right? Have you served your son with it? Have you given copies to the CMO and DYFS? If they try to put him in your home, you call the cops to have the order enforced and cite CMO and DYFS as contributing third parties. I'm pretty sure if you threatened THEM with this scenario, they'd stop making their threats.
So what if the doctors at the psychiatric hospital were "upset" by the judges use of the word catastrophic on record? They are the ones that initially agreed that he should NOT go home. Besides, you now DO have it on record that that's what the judge believed. I'm sure there is some legal ploy you can run if this second judge just overturns the first judge's order. They are not supposed to do that to each other without a due process of some sort, but you'll have to know what to ask for - some sort of motion, or change of venue, or something.
I'd start calling some attorneys right now and leave messages. Some do keep weekend and evening hours and might get back to you sooner rather than later.
by the way is there anywhere you can send your other son for the weekend or a week or two? Maybe your husband and he can go for a vacation? Preferably out of state? Here's my logic.
The worst possible scenario is that difficult child will be forced home. If you are completely unable to stop it, you MUST protect your other child from possibly witnessing your murder, so to prevent further trauma, you sent him to visit with family/friends for a while. "Oh, DYFS worker, you're respecting my refusal and now want my other child? Yeah, sorry, he is safe elsewhere because I HAD to protect him in case difficult child did come home!"