Hooray for Frank! He reunites with his brother on the 10/13/11 episode of It's Always Sunny in Philadelphia.
Yes, folks, Frank has a brother! Who knew?!? Meet him here.

It's Always Sunny in Philadelphia Season 7 Episode 5 Quotes

Dennis: Jesus Christ, Frank, who is this man?
Frank: My goddamned brother.

You are not eating a hoagie. You are just jamming meats and cheeses in your mouth.

Dee [to Frank]