You don't specify the chapter in To Kill a Mockingbird, but I assume you are asking about Chapter 20, when Dill and Scout meet Dolphus Raymond. "This sinful man" fascinates Scout, and he smells good--a mix of "leather, horses, cottonseed"--and she is impressed by "the only English riding boots I had ever seen." Raymond shares his secret with the two children: The bottle hidden in the paper sack with which he is always seen contains only Coca-Cola and not the whiskey that everyone else in town presumes. Scout is shocked by this revelation, and she can't understand why he "deliberately perpetrated fraud against himself." Raymond explains that it is so the townspeople "can latch onto a reason" for why he weaves around town--better for the sake of whiskey than for some unexplainable notion. The children also learn that Raymond sympathizes with Negroes, and he tells Dill that one day he will grow old enough not to
"Cry about the hell white people give colored folks, without even stopping to think that they're people, too."
At the end of chapter nineteen and throughout all of chapter twenty, readers learn many things about Mr. Dolphus Raymond in Harper Lee's novel To Kill a Mockingbird. In chapter nineteen, Scout compares Mayella Ewell to Dolphus Raymond, in the context that Mayella must be the loneliest person in the world because:
"She couldn’t live like Mr. Dolphus Raymond, who preferred the company of Negroes, because she didn’t own a riverbank and she wasn’t from a fine old family."
This suggests that Mr. Raymond is from a fine old family, which may lend him some allowances in behaving outside the social norms of Maycomb. Scout also divulges that Mr. Raymond prefers the company of black people.
In chapter twenty, readers learn that Mr. Raymond has mixed-race children. Scout, Dill, and Jem are discussing the trial, and in particular Dill's moral reaction to the unfair treatment of Tom Robinson. Mr. Dolphus Raymond is sitting under a tree with his brown-sack-covered bottle. He encourages Dill to take a drink of his bottle and Dill reveals that it is only filled with Coca-Cola. This goes against the assumptions they (and most of the town) have made that Mr. Raymond is a drunk.
“Some folks don’t—like the way I live. Now I could say the hell with ‘em, I don’t care if they don’t like it. I do say I don’t care if they don’t like it, right enough— but I don’t say the hell with ’em, see?” Dill and I said, “No sir.” “I try to give ‘em a reason, you see. It helps folks if they can latch onto a reason. When I come to town, which is seldom, if I weave a little and drink out of this sack, folks can say Dolphus Raymond’s in the clutches of whiskey—that’s why he won’t change his ways. He can’t help himself, that’s why he lives the way he does.”
Because Mr. Raymond prefers the company of black people and is unashamed of his mixed children, he says he perpetuates the lie that he is a drunk because it helps people by giving them a reason why he is like that. This insinuates that his actions are not congruent with a person fully in control of their mental faculties. In a way, his actions are cowardly, because people do dismiss his lifestyle choices due to his supposed alcoholism. He tells Dill that he will learn to conform to society as he grows older, and he will not stand up to the invisible social structure either. He says:
“Things haven’t caught up with that one’s instinct yet. Let him get a little older and he won’t get sick and cry. Maybe things’ll strike him as being—not quite right, say, but he won’t cry, not when he gets a few years on him.” “Cry about what, Mr. Raymond?” Dill’s maleness was beginning to assert itself. “Cry about the simple hell people give other people—without even thinking. Cry about the hell white people give colored folks, without even stopping to think that they’re people, too.”