I mildly disagree here. In a formal sense, "Write about you and your family" isn �t correct. We use the reflexive pronoun to refer back to a person who has already appeared in the sentence. Although "you" isn �t written at the beginning, it is understood as the subject of the imperative verb. So, formally speaking, only "Write about yourself and your family is correct".
However, in practice, the formal "rules" are often ignored, driving English teachers crazy, so informally I agree with what Douglas said.
If we take it out of the second person, I think it shows its incorrectness:
He wrote about him and his family.
I �m writing about me and my family.
Bruce
