When my son was super sick (in Children's Hospital for yonks) I actually got to use this PTSD crap to my / his benefit. Up every hour for vitals, hypervigilent as to early warning signs, the half doze/half awake... & 24hr nursing so I could walk out whenever I needed to & chill.
It was after he got mostly better that I crashed. Again. And then I felt guilty when he got worse again... Because the hospital was Soooooo relaxing. Ah. I can sleep. Other people are on watch. And go back to using this shit, again, instead of it getting in my way. And be around other people who get it. Eventually I worked out a balance. And then the rug gets pulled out again and things are sideways. Only thing I know for sure is that things change. But that first time his level of care changed, threw me for a massive loop. Total flat spin. Each time since, though, it's been easier. I think, mostly because I know the stall is coming. I don't deal well with sudden transitions. Even just learning THAT helped.