Many larger buildings in Guatemala are built in the Spanish style around a courtyard, often with a fountain, or with flowering plants as here at the orphanage.
Actually he has it correct. When it's a mixed gender grouping, you do use the male ending unless you want to specifically say how many of each sex. For example, I have two sons and a daughter. If I was talking just generally about having three children, I would say "Tengo tres hijos."