Work Conflict - Should I expose a co-workers bad behaviour?

My husband's sister and I work for the same company - she helped me get into the company. I worked directly with her until we had a major falling out at work about a project. She nearly got fired and I saved her job but the damage was irreversible so I moved on to a different, higher office position within the company.

She tells me all the time about how she keeps getting bonuses and extra time off when she just brags that all she does is sit in her office and play on her iPhone all day and takes the underage teens she works with out and does tequila shots with them. These types of antics are just the tip of the iceberg and I find her actions intolerable. What she's doing doesn't directly affect me but it does affect the company profoundly.

My question is, should I shut up and put up? I don't like the idea of ratting her out but if they find out that I knew about it and didn't say anything, my amazing job could also be on the line.

Have a talk with her about it then if she doesn't change tell then rat her out on what she is doing. But whe you talk to her make it clear that if she doesn't take her job seriously you will report her.

I'd go to your supervisor and tell them. The company could be sued or shut down because of her.

Yes I agree.
Slip a "typed" note under management's door.
Now only if there are no cameras.
Anonymous.
If that won't work. Then type an anonymous note telling what you told us and slip where there are no cameras or to human resources.
But the problem is there's no proof.
Just hearsay.
She could get called in and deny it with a straight face or laugh and say, " are you kidding me? I would not do that."
End of story.
But if you feel that strongly, then do it anonymously.