Please try not to worry, I know it's hard.
1 - as above, the iron doesn't just magically kick in. It floats around in her blood and is gradually picked up by newly formed red blood cells, so I've no idea what they're on about, unless they're measuring it in another way.
I suspect they have decided that actually she could do with a bigger dose. Even so, they need to clarify to your daughter that she won't actually see the benefits for at least a month.
2 - please get some positivity that they're taking it seriously, and looking at her other deficiencies, because by the time they've finished she'll feel a lot better.
3 - you can't grab a random person, but you can ask one of the nurses to note that your daughter needs a proper explanation of how it all works, and what to expect. I don't think they would talk to you because she's an adult, but you could ask to be on the phone/ there, if your daughter is ok with that, too help remember anything she might forget.
Get some sleep. Ward rounds can start as early as 7ish.
She's in the right place, let us know how she goes