I was originally going to invite my brother and his whole family via one invitation since they all lived together, but I have now found that my niece has moved out on her own. I would like for her to be there and will send her a separate invitation to her own address. My issue is my brother's step-son. He gives me a serious case of the willies and I would prefer not to invite him, but that may offend my SIL. I'm probably answering my own question with the previous sentence, but do I have to invite him?