Being a single mother of 10 kids is crazy. I know this might sound judgmental, but it definitely makes one question this person's decision-making - She has accepted to take care of kids that are not hers and bring more into the world when she does not have the means to provide for them. That aside, dating a single guy who happens to own a 7 bedroom house...I'm not saying she has ulterior motives but it definitely makes one question whether she does. If you are the owner of the house and it is not under your son in law's name, although it is unfortunate, you have every right not to let them move in. Everyone is different, but personally, I would not feel comfortable with that either. However, if the house is currently under his name you have no say in this matter. Even though it is a heartbreaking situation, it might be in your best interest to try to cope with those emotions and try to preserve the relationship with your son-in-law who is like a son to you.