Is OTHER wrong in the post ? POST : My nephew and his wife are living with us as we are helping him through college. We are paying their bill.

I came in the house and found her 3 year old daughter drinking coffee that her mother have to her. I toom it away and told her she was not to give her coffee in my house. She said i cant tell her how to raise her daughter. I told her that if i see someone being harmed in my house, i must stop it.
What say you all?