Found out that my friend (cousin) has ana? Or does she cuz she hasnt lost weight?

Hi.. I need some help.. I accidently stumbled accross my cousin karens messages to some 'ana buddies' when i was on her facebook... im so scared.. Her and her friends (some from different states, others from different countries!) wer talking about how to maie throwing up easier and what laxitives to use and some type of 200 calorie a day diet.. I feel like an awful friend. These messeges date back to march, and its almost july! How could i have not noticed anything? Why is she doing this? She has amazing friends and an amazing boyfriend and a really nice body (no homo)... Why is she thinking like this? And why hasnt anyone noticed a change in her?? Shes not anny thinner than she was in march..!? I dont know what to do. Am i supposed to talk to her about it? Shell probably hate me and think i was snooping through her messages but iwasnt!! It was an honest mistaake tht i stumbled across themm..! Please help.. I dont know what to do and im scared<3thankyouu