When my girls were little, and even through middle school and high school, they had a friend like that who lived a few houses down the street. She spent most of her weekends at my house. I was the fun house! Both her parents were OCD and she wasn't allowed to have friends over, and if they did allow it once in a while, it was very uncomfortable for my children as they felt they couldn't move. Both houses had pools but ours was more fun because I didn't mind a little noise. We had pets which she loved. (she even had a pet hamster at our house as she wasn't allowed any pets at home, that she took total care of.) She often spent the night too. I referred to her as my 3rd child.
Now they are adults, they are still close, and I still refer to her as my extra kid.
That being said, you are not required to feed her meals. You can send her home and if you want her to come back after, your daughter can contact her, and if not, then don't. While I allowed this sort of lost child to hang with us, you don't have to. It is your choice.