Flying the American flag upside down is an officially recognized signal of distress.

Most individuals who have served in military service of our nation should recognize this signal.
http://www.usaflagsupply.com/upside-down-flag/

4 U.S. Code § 8 - Respect for flag
(a) The flag should never be displayed with the union down, except as a signal of dire distress in instances of extreme danger to life or property.
https://www.law.cornell.edu/uscode/text/4/8\

What does it mean if the US flag is upside down?
It means the person who hung it is in distress and would like assistance.
https://www.quora.com/What-does-it-mean-if-the-US-flag-is-upside-down