Relationships

How do I tell my sister she needs to move on from her situationship of 5 years?

So I am not exactly sure how long my sister has had this thing going on with this guy but they have been “together” for approximately 5 years. So they have lived together for approximately 3 years, but they are not boyfriend/girlfriend, and it seems like my sister wants to be official but he doesn’t? I’ve heard them argue before and he says he wants to be with someone who will go to church with him, cook, and clean. My sister is not religious and while she does cook and clean she also has a job. He also makes no effort to go to church by himself so I don’t see why he expects someone else to do so? They are completely loyal to each other. They constantly go out on dates, always get each other extravagant gifts for holidays or birthdays, but I feel like he’s holding her back. In high school she was slightly chubby, and once she got to college she began working on herself by going to the gym and eating healthier and she looked great. This was when they met. Now she has put on like 80 pounds, and while she does try to lose weight, I feel like he puts a halt on it. Whenever she is finally making progress and noticeably losing weight he would take her out to eat and never seems like he was trying to help her. Now she wants to buy a house because of a certain situation, but she will be getting financial help to buy it from my family. My mom and I will be living in this house as well. We have found multiple great options, around a month ago we found a dream house with enough bedrooms, acreage, and in the city we currently live in. There was a great price and it was a beautiful home, she seemed to like it but she brought her situationship when we officially toured the home, and after leaving the house with him she suddenly didn’t like it anymore, he was never in the plan to live with us, but all of a sudden after that tour she was looking for bigger houses. Which doesn’t make sense to me if they aren’t official?

Updates
1 y
recently came across an even better house with a better deal. It was a house on foreclosure because it had been abandoned, it would need very minimal work, had acreage, and very nice inside. Upon seeing it she wanted it, she was contacting the realtor as soon as she saw it. We began the process to buy and all of a she didn’t want it anymore. She began saying things she never had before such as “there’s probably something super wrong with it,” and “why would it be so cheap if there wasn’t”
Updates
1 y
Just things I know she didn’t think of on her own because it sounds like things her situationship would say. Even when he toured the original house with us he acted like he was the one that would be buying the house, when he is not involved any way financially.
How do I tell my sister she needs to move on from her situationship of 5 years?
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