People like blythe, Bip and Bitch are talking a whole lot of sense. Brilliant sense.
I'm starting to get a slightly oppressed feeling myself from what OP is telling us. She's just admitted that she does have a good relationship with her daughter most of the time. And yet up until now she's just been telling us what a holy terror the girl is, how she has been forced to repress memories because she's so awful, husband has flashbacks and whatnot...
I am really sorry, OP, I do not mean to trivialise anyone's mental illness, but you and your husband really do sound as if you have a tendency to escalate situations and create drama where it just isn't necessary. I can only imagine what it's like being a 17 year old on the cusp of trying to navigate the world her own way and find her own self...and every time my parents give me instruction it is not because 'it is dangerous' or 'it is not how considerate, mature adults behave' but 'Your father's fragile mental health! If you don't stay in an empty house all night your father will worry and then if he has a breakdown it's your fault! If you give us any teenage backchat your father will have a breakdown and it will be all your fault! If you don't do exactly as we say, you will ruin your relationship with your father and he will have a breakdown and it will be all your fault!"
Honestly, it makes me want to break some doors myself.
The PPs who explained how your husband's condition is his responsibility are completely correct. It is not his fault he's fragile, but it is his condition and he has to manage it - partly for himself, and partly so he can be as good a parent as possible. It's not your child's responsibility to look out for you and live her life around your vulnerabilities.
I know it's frustrating and difficult, especially if your daughter has things to say that are difficult to hear, but parenting teenagers is not about point scoring or face saving (shoutout to the lovely PPs who think it's better to have their daughters streetwalking than giving them any teenage lip at home). It's about protecting the teenager to the best of your ability, while promoting and respecting their independence. It's a difficult line to draw, of course it is, and nobody gets it right all the time. But it really does sound as if you've built a quite oppressive environment where everything your daughter does has to be geared around her father's mental state, her father doesn't have to do anything to try to manage it himself, and the threat of her being responsible for any breakdown or flashbacks or nightmares he has is always being used as a hold over her.
Nobody can live like that.