I want to ask my sister's MIL to leave my house
Do you have a problem with her?
Well, I have had conflict with her since the beginning but it isn't that, she said my older brother is useless which pissed me off.
Even though it might cause problems it is okay to not want people in your house. It is yours and you shouldn't have people that upset you there.
Thanks for the support but I'm afraid what my sister would say.
Your sister doesn't have a say whose in your house. She has to accept that her MIL isn't welcomed there.