Supporting vs. Enabling

Now here's an interesting conundrum.

When M isn't doing well, and is acting on her eating disorder, it's often difficult to know if I'm being a helper or an enabler. (Difficult for me at least.)

One example - she sometimes asks me if this eating disorder is her fault. No, it's not, I tell her, and that's perfectly true. She didn't ask to have this. It's just the result of a weird mix of bad experiences earlier in her life and genetics, and probably other factors as well. But at the same time, she is responsible for her reaction to this disease. She can choose how to respond when stress and anxiety begin to overwhelm her. She can choose whether to talk to me about it or shut down. But, I have to tread carefully here. I don't want to make her feel even more guilty than she already does. And I haven't yet figured out how to help her take on a healthy dose of responsibility without taking on a burden she can't (or shouldn't have to) handle.

Another example - we'll pass someone in a public place who's too skinny, at least to M's eyes. And M will ask me, "wait a minute, why isn't SHE in a treatment center?" If there's a more frustrating question than this, I can't think of it. How the hell should I know if this other girl is being treated for an eating disorder? How do I even know she needs any treatment? And most importantly, what does she have to do with you? I'm pretty sure the safest way to answer this question is to not answer it, but that kind of silence can make for a... curious conversation pattern.

So what do you do?