How to deal with my soon-to-be sister-in-law and her boyfriend?

Have you talked to your sister-in-law about her experience in juve? Even if she didn't stay a long time she could be experiencing trauma from the situation and ordeal. The fact that she attacked her mother is something she has to live with and I am sure she has deep regrets about it. Maybe the best plan of action is to talk to her openly and honestly...if you could get her alone it would be best. Let her talk, open up, and reveal to you how she is feeling and what is going on inside her. She is still young and you know from when you were a teenager it constantly feels like the world is against you and no one understands what your going through or your pain. I have a brother that has problems...he is older than me, completely lazy, and does not take care of himself or his body. I constantly worry about him. They way I handle my brother is I come to him like I am scared of something or want to do something and I need his help. Can he help me through this trying situation so I don't stress out or it feels like too much to handle and I know he is so good at this stuff and can help me do a better job on it. This motivates him to get off the couch and do the job. Of course I can help you the best way would be to blah blah blah. Maybe if you go to your sister-in-law and say hey Im really stressed out about this wedding I have wanted it so long and now the time is coming upon me, do you think you could be my rock during this time? Let me lean on you, vent to you when people are driving me crazy? I know how strong you are, how smart and quick to come up with ideas you are and I need someone in my corner who is not going to be constantly about themselves during my day. I don't know if she is the type of person that this will work on. I hope your day goes off with out a single problem. Congrats also! Good luck