This is nothing you can fix, believe me. There will be times she will be confused partly in the past and feeling powerless. What you shared of what she went through is horrific. Her boundaries are going to be extremely sensitive. Because you are in her environment you will witness some confused states in her.

I have ptsd myself and found it very confusing. I had to be very patient with myself. I would get triggered and would have no idea what triggered me to have a crippling day.

Do you see a therapist for yourself?