What popular American fast food restaurant is always closed on Sunday?

The answer is Chick fil-A.
http://chick-fil-a.com

Link here.
http://www.chick-fil-a.com/

Cathy's beliefs are also responsible for one of the chain's distinctive features: All Chick-fil-A locations (company-owned and franchised, whether in a mall or freestanding) are closed on Sundays.
https://en.wikipedia.org/wiki/Chick-fil-A

Great American!

Has done more for Single welfare Mothers and drug addicted teens than any other person on this Earth.

"When the single mother of one of the boys in his group at the First Baptist Church in Jonesboro, Georgia, was killed in a car accident and left the boy with no place to go, Cathy got the idea to open foster homes. Today, 125 children call him “grandpa” and live in a number of homes staffed by couples that are full-time parents to them."

http://www.truettcathy.com/default.asp