In "A Clean Well-Lighted Place," Hemingway quickly establishes a dichotomy between the two waiters. Although it is not clear from the text who says what in the first piece of dialogue (since the waiters are not yet differentiated), as soon as we are acquainted with their personalities, it is immediately clear that only the younger waiter would think that impecuniosity is the only cause of suicide.
It is by displaying the subtle, thoughtful character of the older waiter in opposition to his brash, unsympathetic coworker that Hemingway communicates his own thoughts to the reader. Hemingway was thirty-four when the story was published, which means that, when he wrote it, he was almost certainly closer in age to the the younger waiter than the older one, but he makes the younger waiter a harsh, unpleasant character, who sneers at the deaf old man and tells him that he should have killed himself.
Although the younger waiter is unlikeable, even he is able to appreciate some of the older man's subtle distinctions and admit that he is right to make them. When he suggests that the old man should buy a bottle and drink at home, the older waiter mildly points out that this is not the same as drinking in a cafe, and he agrees with the justice of this point. By the end of the story, the older waiter's proprietorial, vocational attitude to the cafe comes to seem like a sacred duty, which Hemingway's use of the older waiter as a moral compass throughout the story shows that he approves and understands.