"The boy is his brother."

Translation: Το αγόρι είναι ο αδελφός του.

[ShaoxuanLi]

This is a multiple choice question for me, why is Ο αγόρι είναι ο δικός του αδερφός. incorrect?

[HongNhiNhi]

Because the gender of the article for the word '' αγόρι΄΄is not correct, it must be the neuter ''το''.