There is nothing legally you can really do at this point. Be prepared if you take this back to court, he can fight it also. It won't necessarily mean you get what you want. Even though I think calling the girlfriend mom is stretching it, if it is a long term committed relationship then for all immediate purposes she is being a mom to your son. It may be easier for him to handle when she is doing these things for your son. He doesn't have to explain it to all his friends and cause him discomfort. If she is in the mother roll then she may deserve the title. Because the son does it, it may be easier for your daughter to just follow his lead. I don't think it is done to put you down, but to raise her up. Even though I personally believe they should be married, the person there in the middle of the night, calming fears, cleaning up after them, taking care of them when they are sick, washing clothes, doing homework and all those other things is being a mom. Birth makes you a mother, it's the things that happen everyday that makes you a mom no matter what your blood type says. Ask any adoptive parent. Mom is not a legal term given, mother is. And it does sound like she is being a mom to your son.