Conversation so far:
What sport did Pat Tillman play?
Patrick Daniel Tillman was an American professional football player.
What is he known for doing?
Pat Tillman's service in Iraq and Afghanistan, and subsequent death, were the subject of national attention when he was killed by friendly fire. He was also known for playing football.
What were the findings of the House Committee regarding Pat Tillman's death?
How did Pat Tillman die?
Pat Tillman was killed by friendly fire.

Question: How was his brother killed?
Self-contained rewrite: How was Pat Tillman's brother killed?