Teenager Taught My Niece The N Word, Then Posted A Video Of Her Father Confronting Him

Location: IL

Using a throwaway to reduce any potentially identifying information.

About a week ago, my brother-in-law and his wife were at an HOA meeting where the adults were on the main level of the community center and children were in the basement being watched by some babysitters. During the meeting, a teenager from the neighborhood went down to the basement and taught at least two 2-year-olds, including my niece, to say the N word. To our knowledge, the babysitters didn't intervene. To be clear, no one in this story is black.

After BIL found out, he confronted the teenager and his parents. The parents said they "couldn't do anything." Turns out the teenager recorded the confrontation and posted it to Facebook, lying that BIL was drunk and trying to beat him up. BIL didn't have a drop of liquor that night nor was he acting violent, though he was angrily talking to the teenager (as you'd expect). The video currently has more than 160,000 views, and now there's a second video posted using Ring camera footage which has another 6,000 or so views. FWIW, the teenager blatantly uses the N word in the second video.

Does BIL have any kind of legal ground, e.g. defamation or harassment, based on the videos and the kid lying in them? Or is there any kind of legal ground related to the teenager teaching my young niece a racial slur?

BIL talked to the teenager's principal at his school to see if there's anything they could do, but they said we're SOL since it didn't happen on school grounds and the kid isn't involved in sports or other extracurriculars.