Mr. Raymond tells Scout and Jem that it is Coca-cola and not whiskey in his paper bag and he is not really drunk all the time because he knows that they are not racist and they will understand.
Mr. Raymond is unlike most people in Maycomb because he is not a racist. Since people have a hard time believing he could love a Negro wife and half-breed children, he lets the town believe he is drunk. Mr. Raymond recognizes that children understand that people are people, no matter their race. Since Scout and Jem are Atticus’s children, and Atticus is defending a Negro, Mr. Raymond knows that they are not racist.
Jem thinks, as most people do, that it is whiskey and not Coca-cola in the Coca-cola bottle.
"Always does. He likes 'em better'n he likes us, I reckon. Lives by himself way down near the county line. He's got a colored woman and all sorts of mixed chillun. Show you some of 'em if we see 'em." (ch 16)
When the children actually talk to Raymond, he tells them that his secret isn’t that he’s drinking—it’s actually that he isn’t drinking. Raymond explains why he lets people think this.
It helps folks if they can latch onto a reason .... folks can say Dolphus Raymond's in the clutches of whiskey- that's why he won't change his ways. (ch 17)
In the end, the children realize that Mr. Raymond has found a way to co-exist with the racism of Maycomb, and a clever way to get people to leave him alone.
Mr. Raymond gives us a glimpse of another side of Maycomb. Not everyone thinks the same way, and there are some people besides Atticus that prefer the company of good people to choosing company based on skin color.