How does Walter, Alice's brother, serve as a source of embarrassment in the novel, Alice Adams?

Walter, Alice's brother, has no social ambitions and becomes a petty criminal, who actually deludes himself into believing that he is smart enough to deceive others. He embezzles money from the J. A. Lamb Company and runs away, leaving poor Virgil to repay the money. Before disappearing he is a source of constant embarrassment to his sister. One example of this can be found in the scene where Alice and Arthur are out taking a walk, and they meet Walter coming out of a brothel with a prostitute.