Błędnie: A closer look at the boy's foster family made it all clear to me. His problems were, in fact, an inevitable consequence of emotional coldness and indifference his guards presented. Poprawnie: A closer look at the boy's foster family made it all clear to me. His problems were, in fact, an inevitable consequence of emotional coldness and indifference his guardians presented.
"Guardian" to 'strażnik', choć raczej w języku formalnym i znaczeniach metaforycznych. Słowo to oznacza także 'opiekuna', co ilustruje powyższy przykład. "Guard" to 'straznik, wartownik', ale już nie 'opiekun'.