They will stand up to any person saying such things. But they have also been taught that there are and always will be people in our society who are stupid and say ignorant things. They have been taught tolerance. Tolerance of ALL people.
Words and actions have consequences
In situations like this when others are around, **NOT** saying anything could be construed as going along with or agreeing with the foolish idiot's remarks. That's why standing up to it is important.
Running to the AP does not help the global problem or even the current situation. When will people understand that all of this running to the authorities is making the systemic problem worse...
I find peer pressure to be an effective way to deal with people like this. A long pause combined with a withering look and the phrase "Did you really just say that?" can be more effective than complaining to an authority. I have a BIL who used to make horribly sexist jokes. I would just look at him with the "Really?!!" look. He stopped making the jokes. At one point he jokingly said, "You don't like me do you?" I responded with "I don't like your jokes." He apologized.
I think it is a very small school and small senior class. When my kids were in a grade school,with the same 48 kids (then 40, then 38), you pretty much had to deal with everyone, even the girl who stole things and the boys who were a little rough.
While some here may find such a school environment to be strict, it was actually a big selling point with many parents who didn't want the alternative, local public schools where the prevailing attitude among educrats/critical mass of parents was "let kids be kids" to the point classrooms were in complete chaos, K-8/12 kids were getting beaten up/knifed/shot on a regular basis, and the same educrats/parents had the same "It's the fault of the victim to being offended/feeling bad/etc or "going to authorities is bad".
As to the OP's situation, if this were October I might have a conversation with the school so they could keep an eye out for situations like this. It's late May. What do you expect the school to do at this point, not let the kid graduate based on only the word of a classmate?
The zest expressed by most posters here in rooting out thought crime would be funny if it were not so obviously dangerous.
I'm not advocating he not receive his diploma, but walking across that stage is a privilege , not a right. IMO.
@carolinamom2boys The boy is a nominee of the valedictorian/Student of the Year (even though D has higher GPA than him and obviously he is having some Cs this semester) and I believe he and my daughter are both Scholar Athlete of the Year. So, for sure he will appear on the stage for more than once.