I think I heard my white friend say the n-word last night?

Hi I'm a 27 white male and I was dropping off my white friend in his 30s last night after going to the gym. We were pulled over by a police officer last night for a speeding ticket and as I was dropping my friend off I think he said "hey if you need a n-word to go with you to court lmk I'm there for you" it was so quick that I didn't have a reaction to it until after he got out the car. I'm in a relationship with a black woman and he knows this and he actually works with my partner, and seemingly really likes my partner. What should I do? I may have been hearing things but maybe not..