He ain't trying to hear that BULLshyt she talkin.
My advice woulda been
Catch that boy by himself and tell him it was just jokes but don't talk about moms. If he seems shook and or apologetic then you can apologize for stepping to him like you were gonna beat his ass. Dap it up and Kim.
If he talks unapologetic let him know he gonna force you to discipline him so it's best they just cut out crakin on each other. Then check whoever tries to instigate.
But that's diplomatic.
Probably an approach designed from training years of Brazilian Jiu-Jitsu