They may not be his beliefs. I grew up with Archie Bunker as my father. I knew every derogatory term for minorities, other religious groups, etc., but didn’t know they were hurtful. I lived in a community that was heavily Polish, and we all told Pollack jokes because we thought they were funny. To others, they might not be funny.
We learn things as we grow older too. A friend who has children adopted from Africa taught me about blood diamonds and I was easily convinced not to buy diamonds. Dream catchers are a popular trinket around me but are a religious symbol to Native Americans and should be treated as such.
This kid is 18. He might just need to be told that some of the terms he’s been using aren’t acceptable.