Continuity mistake: In the opening scene when The Dude's head is repeatedly shoved in the toilet, almost all of the water is pushed out of the bowl and it's nearly empty. Soon the bowl is once again full, even though the toilet had not been flushed, which is the only way the bowl is normally refilled.
Continuity mistake: When the Dude first meets Bunny by the pool, her lounge chair is in the bright sunlight, directly facing the sun. When he walks away, her chair is in the shade and the shadows show the sun is now to the side.
Answer: Generally, he means that the boy, Larry Sellers, is disgracing his family (Walter has huge respect for the boy's dad, but considers the kid a dunce). Specifically, Walter is blaming Larry for his father struggling to breathe; that's Larry's dad in an iron lung in the background. Walter and The Dude become louder, more insistent and more vulgar, but the kid still blankly refuses to answer, and all you can hear is the iron lung pumping in the background. Frustrated because the kid isn't intimidated, Walter lashes out: "You're killing your father, Larry!"
Charles Austin Miller