The Jacket - S2-E3
Continuity mistake: Jerry asks George in front of the fridge "You don't know Robert Schumann?"; between shots his shirt's collar is suddenly fixed, as earlier it was leaving the tie hanging out at the back. (00:05:50)
The Jacket - S2-E3
Continuity mistake: When Elaine's dad says "Pipe down, chorus boy" to George, suddenly a hotel staffer in red appears in the recess by the lamp. In another blatant continuity mistake, in the shot that follows George is suddenly without glasses. (00:17:50)
The Jacket - S2-E3
Continuity mistake: In the shot when Jerry points to Kramer where the ruined jacket is and he walks across the room to go check it out, the box of Ritz crackers is facing The Opposite direction than before, and in the following shot he is holding it in a different way too, by the top of the box instead of the bottom. (00:19:40)
The Jacket - S2-E3
Continuity mistake: Jerry powers out of George's grip on his arm to go to the bathroom. Notice Jason Alexander 's right arm; when he is awkwardly smiling at Elaine's dad all of a sudden the coat is entirely under it, while he had the elbow in the middle of it earlier. (00:12:30)
The Jacket - S2-E3
Continuity mistake: When everyone gets up from the lobby seats talking to Alton, George's coat is folded on his arm in two different ways that alternate between shots. (00:17:40)
The Jacket - S2-E3
Continuity mistake: Elaine's intimidating father gets up and tells Jerry and George in his gravely voice "I'm going to the bathroom." The newspaper on the table changes spot before and after said shot. (00:15:30)
The Jacket - S2-E3
Continuity mistake: At the end of their strategic break in the men's room, George tosses his paper towel in the bin to the right; however the previous shot ended with Jason Alexander turning around having the towel in his left hand and glancing towards the basket on the left. (00:13:55)
The Jacket - S2-E3
Continuity mistake: In the reaction shot with Alton Benes scoffing at George and Jerry's sissy choice of drinks, a woman with a coat in hand is walking behind him, towards the door. In the next shot, no trace of the woman, just someone in a bicolor puffer. (00:10:25)
Chosen answer: George does mention his brother in the episode "The Parking Space". They actually really never mention anything that contradicts the fact he had a brother though, it just isn't mentioned.