vulgar kindergarteners

Brittany • Mommy to a wonderful 12yr old boy, 9yr old boy 7yr old girl 6yr old girl and 3yr old girl. Due March 11th 2023 with a boy.
My son has a boy in his class who's father is in prison for molesting his daughter. This little boy says things like he wants to have sex with a girl named Caley in his class, he told another little girl he wanted to kiss her boobies and vagina and told my son that he did kiss another little girls privates. He calls my son a dick and a dumb fucker and puts hands on my son almost daily. My son has a bruise on his back where this kid bit him. I've tried so hard to be understanding that this 6yr old little boys home life is bad, but I'm am livid. I want to punch his mom in the throat. I have requested that this little boy not have contact with my son anymore, but they are in the same class. I feel like CPS needs to be called cuz of the sexual things this little boy says. I've told the school psychologist what this little boy says and about his Dad and they don't seem to care. I don't know what to do. This little boy makes my son beg me to let him stay home from school. I just want to snap. What would you do?