My friend is really mean to animals?

Well my friend, Bre, is really mean to her animals. Not mean in a violent/neglectful sense, but sort of.... ?! She's not very mature, so I can't sit down and talk about it with her, but she had WITH HER DOG! I feel so bad for those poor animals, and at the same time I feel sort of bad for her since normal healthy teenagers don't do that.... Seriously. What do I do?!