I totally understand not being able to pump much. When Morgan was a baby, I had so much milk he would gag and it would run out of his mouth (and it wasn't overactive let down, this would be all the way through the feeding lol), and yet I could only pump an oz or less, even if I was engorged.
Any little bit she can give Elf is going to help. Preemie milk is way different than full term milk. I had to pump and suppliment Morgan until he was six weeks old and he finally figured out how to nurse. It was really hard (and he wasn't in the hospital all the time either) and I wanted to give up so many times, but in the end it was well worth it and he ended up nursing until he was almost 2. So if she really wants to BF, encourage her as much as you can to just stick with the pumping until Elf can nurse. Even if it seems like she's hardly getting anything, any little bit she's giving her is helping her to get stronger, and once she can nurse, she will be able to get her supply up in just a few days.