@Aranan when you first enter the world of ED, the statistic that always seems to get thrown is the awful one about anorexia having the highest mortality rate of any mental illness. However, actually the recovery rates aren't as awful as other conditions. For example my friend's son has a level of ADHD and OCD that makes normal life near impossible and I do wonder if he'll have that for life. The prognosis for anorexics is much better. About half make a full recovery, 30% recover but with some issues and the remaining 20% don't.
I don't know what constitutes a partial recovery given that lots of people/women have issues around food and body image.
One in 5 not recovering sounds pretty awful but those are very bald statistics and if you drill down, the odds are better for your DD. The younger the sufferer (ie in their teens) and the more support they receive, the better the odds for recovery. It's much, much harder for adults to recover. We have a 20something relative who expresses envy that DD has us to monitor her eating as she finds it hard to do alone.
Our experience with DD has flushed out a lot of ex anorexics that I had no idea about. They all seem to have come through with their fertility intact and now lead normal, mainly happy lives. A couple of them are weird about food - brilliant and generous cooks yet still very thin themselves, but the rest seem fine.