A.D.
I know they are family. But your child has told you she does not want to be around Madison. And for good reason. She's getting physically bullied. You've seen it. I would be livid. Stop bringing your child around these people. Do not invite them to your home or initiate getting together with them. Leave your daughter with your husband or in someone else's care the next time you will be seeing your sister and niece. When someone asks where she is, I would be totally blunt. "She does not want to be around Madion." Let them chew on that. Especially Madison. Children should not have be forced into keeping company with bullies. If they ask you "why?" I'd simply tell them she doesn't like how Madison treats her, and she has your permission not to attend. If they want to blow up and make it into an argument, I'd leave. Let your sister have a conversation about why her cousin won't come around anymore, after the initial shock. Maybe taking your daughter out of contact for awhile will have an impact. At the point you decide to bring her around again, I would NOT allow them to play out of my sight. Sadly, there have been times I have had to do this around my kid's cousins. Thankfully, it was a phase that passed. Hopefully, as the girls mature, it will be phase in your family too.