What steps could health professionals have taken to assist the nurse who was in trouble?

During Alan’s operation, a nurse knowingly replaced the painkiller fentanyl, which was ordered to treat Alan, with water. This nurse placed Alan in physical jeopardy because of his own desperate need to obtain an opiate drug
to satisfy his drug addiction. This was not the first time that the nurse had
stolen a restricted drug for the purposes of self-administering it. A number of complaints had been made about the nurse while he was working at another hospital, including professional misconduct, impairment due to drug addiction and lack of good character, which rendered the nurse unfit to practise.
Questions
1.What steps could health professionals have taken to assist the nurse who was in trouble?
2.What policies should the health service have to protect patients from health professionals
3.who are drug-addicted or impaired?