It is true that the devil can give riches to those who follow his ways. It is also true that he will work to prevent riches getting into the hands of godly people who will use it for evangelism.

The only way to overcome Satan's power on earth is to PRAY MUCH, fasting also at times, and focus on Jesus and do what God says. It is not an easy path.

You could try reasoning with your friend but if he loves the world more than Truth it will not work easily. So pray and seek opportunities to talk with him about eternal things.