Understanding Character through Stage Directions

In the dramatic play Death of a Salesman by Arthur Miller, stage directions often provide vital insights into the characters’ internal struggles and relationships. Consider the following segment:

WILLY stands alone on the stage, his silhouette outlined against a stark light. His hands tremble slightly as he looks out into the audience, a vacant expression on his face. The room is silent, save for the distant sound of traffic.

With this in mind, what does this specific set of stage directions most likely intend to convey about Willy's character at this moment in the play?