advice?

So my best friend has been struggling with anorexia for a few years now. Two years ago she spent 3 months in a rehab center in Tulsa, and last night she told me that this morning so would be leaving to go to Denver(we live in Arkansas) so go to another rehab center to get more help. I'm extremely upset because she's my best friend, yunno?  She's scared, and I'm scared for her, but I don't know what to do. I keep telling her how much I love her and how she's not alone, but I don't know if there's anything else I could say or do to help. Is there anyone who's been through something similar who knows what I could say or do to comfort her?