If thats what makes you sleep at night- Commonly used phrase to make peers nearby laugh. But mainly it means what your trying to say is impossible and would never happen.
Kid :"DUDE I CAN DUNK NOW"
Other Kid: "Yeah if thats what makes you sleep at night."
Other kids: "BHAHHAH"
Fogey/fogy /fougi/ sl. (early 18C+, orig. Scot) old-fashioned, stuck-in-the mud.
Person with old fashioned ideas which he is unwilling to change: Come to the disco and stop being such an old fogey!
You think me an old fogeyand an old tory, his thoughtful voice said. I saw three generations since O’Connel’s time. I remember the famine. Do you know that the orange lodges agitated for repeal of the union twenty years before O’Connel did or before the prelates of your communion denounced him as a demagogue? You fenians forget some things. (James Joyce, Ulysses. PenguinBooks,1992. p. 38)