Hi again. I was trying to ask about a friends weird behaviour and advice.?

So here we go again. A best friend of mine has been acting weirdly and she is breaking up with old friends. The problem is her new friends are not a very good company, she is not listening to anyone, she has really become stuborn. I tried talking to her but that isnt helpin. She thinks her new friends are great and thats making things worse. So any advices? And is it any better?