1) Make sure you keep your personal information safe. Don't expose your information on third-party platforms and social media
2) Ensure you secure your phone from hacking and phishing. Avoid clicking on links randomly without checks.
3) Don't be greedy because scammers always come up with enticing schemes with high profits.
4) In any case of hack or security compromise ensure you go through the right recovery and security process.
5) Be sensitive and avoid making hasty decisions. When you receive such calls or messages contact the people involved and don't rush into action. Your friend was able to outsmart the scammers because he didn't allow the situation to distort his sense of reasoning. He had to confirm the situation with you first.