Deb, I am probably the wrong one to give advice on mothers. You sound like you have a lot of issues as I have with my mom. People still use the word here. In some cases the black humans use it more than other humans. Just like it shows in movies. It sounds like she is using the word to push your buttons, maybe when she uses the n word you could use the f word or the s word. If you don't know what these words are, fake it.
Rockon