You won't feel good about ratting your sister's boyfriend out so I am glad you are not going to do this. Love your sister as best you can, stay out of her relationship issues, and pray that she will come to her senses soon. You know the drill ... the more you rag about how bad the boyfriend is, the more likely she will be do dig her heels in and defend him. He will mess up soon enough and be back in trouble with the law without your reporting him.

When you get your sister back, just hug her and love her without criticism. Meanwhile, consider doing some volunteer work where you can share the good you have to offer to people who are in a position to accept it.