HELP FairyGodBoss Ladies!

HELP FairyGodBoss Ladies!

I need your advice, I am a new manager in HR at a major corporation. As an older person, and I say this is because everyone else is in their early 20's to late 30's and they are a group of diverse managers. Some more of one ethnic group than the other. I am dealing with one young man that is extremely sarcastic, gaslight me and some of the associates and when I address the issue he takes offense and turns the table like he's the victim. Example, he told an employee from another country, I have to be equally hard on you because your people have a hard time understanding. He has insulted so many of the associates. I have approached the associates in question and they are afraid to talk to me because his father use to be one of the VP in the company and he got the job through the who you know. He's immature, tells managers they don't know what they are doing and they will be better off working in a role that he see fits for them. I have pulled him into my office and talked to him and went over the handbook and policies of unprofessional conduct, diversity and inclusion training etc. I even went to my direct report for support and he stated and I quote "maybe I misunderstood what he was saying because I noticed other managers laughed at his comments". REALLY! I am appalled by the fact my manager is accepting this. I just started this job and I worked hard to get it. Please advised!