I have a friend that is suicidal she hasn't eaten in 3 days and she took 15 antibiotics tablets will she die?

Few if any antibiotics are likely to be fatal in any dose. However, of course this person needs immediate medical care, as well as loving attention (which might include getting her into appropriate care) before she tries some other kind of self harm. Good luck to both of you.

Recommend an immediate visit to a hospital emergency department to deal with the overdose, and concurrently, a full evaluation by a psychiatrist. She is clearly at risk for further suicidal gestures and/or intent. This is indeed an emergency.