Hi mee8ka,
Food in South America is of excellent quality. Your son should not be concerned at all. Lots of restaurant serve simple but fine meals. There is nothing to worry about.
Argentina produces probably the best meat in the world and their 'asado' (barbecue) is paradise for meat lovers. Other countries like Peru and Ecuador serve besides local meat dishes like 'cuy' (guinea pig) also great seafood dishes.
You can read more about
food from Argentina,
food from Brazil,
food from Peru and
food from Ecuador on our site.
Feel free to ask more questions. I'll do my best to help you out.
Best wishes,
Mark