Tell him that we evolved from fish.
The whole idea of evolving from monkeys is false in itself because it suggests that this was the starting point as well as making people think of modern day monkeys rather than a common primate ancestor. So telling him that humans, monkeys, apes and everything else also evolved from fish will put the whole process into a larger prospective.
http://www.bbc.co.uk/news/health-13278255
Basically don't let him dictate the argument. He's arguing about a definition, i.e. of monkey. What's important is an understanding about how evolution works.
The whole idea of evolving from monkeys is false in itself because it suggests that this was the starting point as well as making people think of modern day monkeys rather than a common primate ancestor. So telling him that humans, monkeys, apes and everything else also evolved from fish will put the whole process into a larger prospective.
http://www.bbc.co.uk/news/health-13278255
Basically don't let him dictate the argument. He's arguing about a definition, i.e. of monkey. What's important is an understanding about how evolution works.