Ethical question regarding relative hiring policy?

I have a friend who wishes to remain anonymous and wants opinions about this issue. He works part time for a big company in operations at the entry level and he has an uncle that works in this company too who is in upper management. Before he got hired, he had no knowledge of company policy and did not want help from his uncle so he didn't tell him that he is pursuing a job for this company. During his interview with H.R., he mentioned how his uncle works for the company and holds a position in upper management and he got hired two weeks after his interview. After a month of working with the company, his father talked to his uncle about how he got the job and his uncle responded that he was surprised that he got the job in the first place because they don't usually hire relatives. Curious about what his uncle said, he researched through the company's internal website and he did in fact find a relative hiring policy within the company that promoted fairness and prevents favoritism from happening. In the policy, it does state that if a relative has a position in upper management other relatives should not be hired. So my friend wants to know if it's unethical if he keeps his job despite what the policy said and what he disclosed to H.R.