Washington (CNN) Six siblings of Republican Rep. Paul Gosar delivered a stark message in a new television advertisement: Vote for their brother's opponent.

The Democrat challenging Gosar in Arizona's 4th District unveiled a new ad Friday that features Grace, David, Jennifer, Tim, Joan and Gaston lambasting Gosar over Social Security, health care, water policy and more.

"Paul's absolutely not working for his district," David says.

Then comes the big reveal: Gosar is their brother -- but they endorse David Brill, the Democrat running against him.

Paul Gosar is the oldest of 10 children.

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