。
She lost her son in the war.
Literal
She [topic-は] war [in-で] son [object-を] lost.
A short but powerful sentence. The で marks the war as the circumstance in which the loss occurred. 失う (うしなう) means 'to lose' — more literary and weighted than なくす, carrying a sense of irreversible, significant loss. The simplicity of the sentence mirrors how grief is often expressed with understatement rather than elaboration.