Let me preface this by saying, I am NOT trying to judge the situation at hand, I just merely need help on what to say or do or if there is anything I can do.
My family and I (3 boys, husband and baby on the way!) currently live in my families old house that I grew up in. We live with 2 of my sisters, ages 24 and 21. While we have really liked living here due to being right across the street from the elementary school that my son goes to and being down the street from our home parish, there is one thing that really bothers me. My 24 year old sister's boyfriend spends the night probably 3-4 nights out of the week here at the house in her bed. Believe me when I say that I am NO angel and that I was promiscuous in my younger days and even got pregnant before getting married. I did end up marrying the father who has now been my husband for 7 years :) So like I said in the beginning, I REALLY have no right to judge, I am just concerned for her. My parents who own the house have told her that they did not want him spending the night and yet he still continues to spend the night. I have also talked to him and expressed that my husband and I were not comfortable with him spending the night either especially since we have 3 little boys in the house who ask questions. She has told me that they have NOT had premarital sex and she won't have sex until she is married and I believe her. I just worry about her soul and how this will affect their relationship especially if they decide to get married. She is a practicing Catholic and attends Mass regularly and confession and truly loves her Faith. He is not Catholic but attends Mass with her sometimes and says if they were to marry he would not convert but raise their children Catholic if she wished. (he is a non practicing Jew) When I have talked to my parents about this, they say that they talked to her about it and that she know how they feel but that is it. I believe that neither of them feel right to be talking to her about this since my dad got his girlfriend pregnant at 18 and my mom lived with a boyfriend or two so they think, "who are we to tell her not to do it." My husband, kids and I are planning on moving in the summer after our 4th is born so I just wonder if I should put up with it since we are moving out or if I can say anything to her that can make her see what she is doing is jeopardizing her eternal salvation as well as her relationship.
I apologize if I don't make a lot of sense, sometimes I ramble when I'm nervous! :D
Thank you in advance for your prayers or helpful hints.