Answer:
They can buy a house in Cartagena, Colombia, in the historic center. (Ellos pueden comprar una casa en Cartagena, Colombia, en el centro histórico).
Cartagena has a warm weather all year round, with an average temperature of 82 Farenheit / 28 Celsius.
The historic center is characterized by its colorful house in colonial spanish style. These houses are on average 200 years old, and have great cultural value.
Spain would not work so well because houses there are mostly white, and your parents want colors. Same for France because houses there tend to come in various shades of brown and white, and Argentina does not really have pretty beach houses, and the sea there is cold.
