One of the ways to create those boundaries for yourself is to understand that you can only do so much to help this person, and recognize your own cues and gut reactions to understand when that person is asking too much of you. When you feel like you’re covering for someone, that’s a problem; when you feel like you’re trying to manage their addiction, that’s not a good boundary; when you feel like you’re always cleaning up after someone else’s messes, that’s an inappropriate boundary.