Ask the Feng Shui master if his brother's children can come to my house after the full moon.

I think so. It's no problem for his brother's children to stay at my house without a full moon. In our countryside, it is no problem for two brothers or even brothers to live in the same house, because the brother is a incense, that is to say, a bodhisattva, so there is no problem. Don't worry! If the wife's brother comes to his house, if there is no full moon, the brother and daughter-in-law should pay attention. Only children should not be jealous!