I know this can be maddening. Detaching from a difficult child's health issues is a unique situation. On one hand, your mom instinct wants to jump in, take care of them, get them medications, tell them how to take care of it, just like you did when they were little. You're frantic at the thought of them doing permanent damage to their bodies (or worse) because of their poor choices. On the other hand, they are adults, and have to make their own decisions, even when their decisions cause their health to worsen. Unfortunately I've watched this with both of my girls. With Oldest, it was neglecting her ostomy care and general health and getting infections, abscesses or intestinal blockages. With Youngest, it was not taking her seizure medications or drinking too much (which made her seizure medications useless), and having seizures. "Natural consequence" of poor health choices can be deadly. Yet, I've had to learn that even in such frightening situations, I have to step back and let them suffer, literally sometimes, in order for them to learn to take care of themselves. I even stepped back and stopped meeting them at ER for every emergency, because at one point it was just happening too often. I realize that sounds cold and heartless, but for my particular situation, it was just the way I had to learn to deal with it. I have to take things on a case by case basis now. The good thing is, both girls have gotten better at taking care of themselves overall, and those situations arise less frequently.
For (some) difficult children with health issues, their health becomes yet another means of manipulation. They call to throw us into a panic, then refuse to answer our calls when we call back to check on them, throwing us into another panic. I try to tell myself that "no news is good news," and that if something bad happens, it won't be my fault. I sometimes worry that I've simply become a heartless B ... but... it's how I've learned to cope, personally.
Hugs.