Hey @JoyousCyanCat sorry you've found yourself here. I would recommend you read Eva Musby's book, it's available on Amazon. There are also several chapters available on Eva's website while you wait for it to arrive, as well as some really useful YouTube videos.
The road to recovery is sadly usually pretty long. The work will be done by you at home, and the FBT appointments are designed to help you to do it, but they don't target the ED directly if that makes sense.
There are a few ways of getting them to eat. We took what's often known as a 'life stops until you eat' approach. So that meant that every meal and every snack had to be eaten in full, and we would sit with our daughter and wait for this to happen, offering firm, but compassionate encouragement. In the early weeks and months this was met with extreme distress, aggression, attempts to discard or hide food. It is very hard to keep going, but necessary, as recovery depends on the brain having what it needs - calories and fat.
I supplemented all meals with as many calories as I could - we went through blocks and blocks of butter, and many pots of double cream a week. I used to make a shake for afternoon snack with a small pot of haagen dazs, 100 mls of double cream, cashew butter, sunflower oil and a spoon of nesquick- that's at least 800 calories in a very small glass. They are not allowed to be involved in food choice or preparation, and must eat everything, not leaving even a mouthful. In the beginning they will want to make sure it's safe for your daughter to increase her calories - there can be a risk of 'refeeding' syndrome when they haven't been eating much.
fbt doesn't suit everyone, but it does have good evidence for recovery. My daughter couldn't have cared about the threat of hospitalisation - the anorexia voice is very loud at the start. Nothing really gets through to them. Eating is the only real way to get to recovery.
We kept our daughter off school for about 6 weeks, and then she was back mornings only. We are a year into this, weight restored for about 5 months now, she is doing much better mentally, and she still can't manage eating without some supervision. It's something we are working on in the second phase of fbt. So I'd be cautious about the idea of her managing to eat anything while you aren't with her. My daughter could even manage to hide food while we were sitting next to her - for a few weeks we had to watch every mouthful going in, and check it was all gone by checking in her mouth at the end of a meal.
Sorry to be the bearer of grim information. Recovery is long and hard, but it is possible, although we aren't there yet. We are about 13 months post diagnosis here.
Use this thread for anything you need - advice, information, to vent, get support. It was probably the best source of information and support for me.
Good luck