This happened to me too at exactly 5 days old. Ds refused the breast and went for 11 hours without milk.
WHat I did was express every 3 hours and syringe or cup feed him. No-one ever knew exactly why it happened, it could be he was too small, distressed by my let down or objected to having his head handled.
Offer the breast each feed. I would actually say to cup feed a little first and even drip some milk down her breast to encourage her. A frantically hungry baby may not feed well. LOTS of skin to skin contact, to try and turn it into a positive experience. One thing she could try is taking the baby into the bath (re-birthing). If she or the baby gets distressed at all, stop and cup feed.
Is the baby jaundiced? It can become a vicious circle of sleepiness increasing the jaundice increasing the sleepiness.
The MOST important thing is to get milk into the baby. EBM is preferable and a cup is preferable to a bottle. When this sort of thing happens there is a tendancy to feel like you have stumped all the experts and you wonder whether the baby will ever feed. Dh certainly said to me that I must face facts that ds was not going to feed.
Does she have enough cups/access to them? I could send some if need be.
Lastly, she CAN get through this. It will be tough depending on how long it lasts (in my case just over 4 weeks and she will need incredible support.
I am only half way through my peer support training, but if she wants to talk on a mum to mum basis to someone who has been through this then feel free to contact me julief @ netmums dot com