Mental illness, a serious issue in the United States due to millions suffering, has occasionally been the topic of comedy fodder, including "'''The Fat Guy Strangler'''," an episode that establishes Patrick Pewterschmidt as Lois' brother.

Basically, the episode is about Lois discovering that Patrick is her long-lost brother, and that he had been institutionalized after suffering severe post-traumatic stress disorder when he claims to have seen a man dressed and acting like and even identifying himself as Ralph Kramden (of TV's ''TheHoneymooners'') seducing their mother. The discovery comes when a family photo from Lois' childhood is knocked over and, in picking it up, sees a young boy she doesn't recognize but senses the boy has a connection to the family; Carter and Betty initially bluff an explanation but soon the truth is revealed.

Lois gets Patrick released, believing him to be sane, but as it quickly becomes clear Patrick is mentally unstable, Peter triggers a flashback when he begins acting like Jackie Gleason's signature TV character. Patrick snaps and starts murdering overweight people throughout Quahog, leaving Peter's live in danger.

Meanwhile, Peter stubbornly refusing to go on a diet, per his doctor's orders charters the "National Association for The Advancement of Fat People" (NAAFP), to help aid the cause of overweight and obese people. Naturally, things don't go well, but that's mild compared to what happens when Patrick begins his rampage, killing or severely injuring several overweight men who are at the Griffins' home. Lois refuses to believe that Patrick is involved, even after seeing a news report and Brian even going so far as showing her a room full of victims inside their home. Lois finally snaps out of her denial and agrees Patrick is a danger to the community and himself, and that he needs to be caught. A trap is eventually set up, Patrick is captured and re-institutionalized.

!! Tropes associated with this episode

* ContinuityNod: Brian throws a rock at Peter for rolling up the window when he tried to jump into the General Lee in To Love And Die in Dixie.
** WhatCouldHaveBeen: Originally it was going to be because Brian was in a carrier cage on a plane to meet Patrick and Peter pissed on him.
* DudeNotFunny: Several jokes throughout the episode about the mentally ill.
* InnocentlyInsensitive: Peter is a {{jerkass}}, but he had no way of knowing that Patrick had a mental breakdown due to a guy dressed as Jackie Gleeson. Quickly just turns into a full blown {{jerkass}} since Peter does it again right after Patrick has been stopped.
* OnlySaneMan: Brian realizes straight away that Patrick is the Fat Guy Strangler and tells Lois that it's pretty clear it's him. Lois however is in full blown denial.
* TooDumbToLive: Yes Lois, your brother who clearly has a problem with fat guys due to his backstory he explained to you isn't the Fat Guy Strangler, just ignore all of the evidence until Brian has to practically spell it out for you.
* ShoutOut: To:
** ''TheHoneymooners'': The Jackie Gleason look-alike (and later, Peter) impersonating the show's signature character and mannerisms, including "Pow! Right in the kisser!"
** BillyJoel: The "caveman who invented singing" performs Joel's 1984 hit "The Longest Time," a cappella style.
* {{Trigger}}: Peter's insensitive impersonation of Ralph Kramden (from ''TheHoneymooners'') triggers Patrick's trauma of seeing his mother and a Jackie Gleason lookalike having an affair ... and sets off his homicidal rage against overweight people.